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The Pain Spectrum
Sometimes pain can seem so simple.
We trip, twist our ankle, and it hurts. It hurts in a specific place. It hurts when we put weight on it or bend it in any direction too far. Over time it gets better on its own.
Simple.
Other times pain can feel very complicated.
Sometimes there was no event at all. No twisting of an ankle, or pulling of a muscle. There was just a pain that showed up one day for no apparent reason, or a pain that came on gradually and didn’t go away or got progressively worse.
This can leave us perplexed, frustrated, defeated.
Many times it's somewhere in between.
Indeed there are many times when the pain falls somewhere in between these two poles.
But these two poles are important to understand. They are two ends of a spectrum of pain, and the expectations and management of pain are different from one end of the spectrum to the other.
The more we understand this pain spectrum, the more we can make wise decisions about what to do when pain shows up or persists.
The Pain Spectrum*
One way we can think of pain is by classifying it in terms of its position on a scale between two extremes.
On one end of the pain spectrum is what we’ll call Simple Pain (2,3).
Simple Pain is pain that:
Usually has a clear cause or inciting event
Has a localized or predictable location
Is influenced by a few predictable factors
Has not been present for very long (~< 3 months), and has improved over time
Simple Pain is clear, predictable, and improving.
On the other end of the pain spectrum is what we’ll call Complex Pain (1).
Complex Pain is pain that:
Has no identifiable cause or inciting event, or has been present for a long time (~> 3 months) with minimal or no improvement
Occurs in diffuse, changing/fluctuating, or unpredictable location(s)
Is influenced by many factors or appears unpredictable
May be accompanied by increased sensitivity to other stimuli (sound, smell, bright light, chemical stimuli, foods, heat/cold, stress, emotions, mental load)
Complex Pain is unclear, unpredictable, and lingering or worsening.
Simple Pain, detailed
Simple Pain is what we often think of when we think of pain associated with an injury.
This is the ankle sprain detailed above. This is the knee scrape that we’ve had many times before.
Another classic example of simple pain is pain from a herniated disc.
We are helping our friend move, and while lifting their ridiculously heavy dresser we experience acute, severe pain (clear cause/inciting event)
The pain is in the low back pain and radiates into the leg (predictable location(s))
The pain is worsened by bending, as well as moving the back in other directions too far (influenced by predictable factors)
After a few days of agony, it starts to get better. We slowly return to normal functioning, and within a few weeks, are more or less back to life as usual (improves over time)
But sometimes things are different.
Complex Pain, detailed
Complex Pain, on the other hand, is not so clear.
It can be confusing, perplexing, mysterious. It can seem to follow no apparent pattern and can leave us confused and frustrated as we try our best to figure it out and navigate daily life.
My low back pain is a pretty good example of complex pain. It started when I was 18. There was no specific identifiable event or injury. It has been present most days of the week since then. The location is diffusely the low back, but it can change sides, be more localized or diffuse, and sometimes move up to my mid-back.
It is influenced by many factors:
Position. Sitting is rarely bothersome, standing is often bothersome after ~10 minutes (but not always)
Activity levels. If my activity levels dip, the pain tends to get worse
Sleep. Too much or too little sleep tends to make it worse
Stress. When my stress levels rise it tends to get worse
Other. One of the biggest triggers is my sense of control. I’ve found that If I am in control of how long I stand/walk, I will have less pain than if I’m not. Going to HomeGoods with my wife is a perfect example of this.
Random? Every so often the pain will get worse seemingly randomly. This happened just recently: Nothing changed in my routines, and my stress levels were in check, but for some reason, the pain worsened for about 3 days. At first, I thought I was getting sick, but I never got sick, nor did I figure out what may have triggered it to get worse.
Finally, I do consider myself to be a sensitive person. I am fairly sensitive to cold, stress, and certain types of foods, and I tend to feel my emotions and the emotions of other people deeply.
A Spectrum
You may be reading this and thinking that the pain you’re experiencing doesn’t neatly fit into either category. This is normal, and why these two pain types are on a spectrum.
Some examples of pain that may fall somewhere in the middle are:
Shoulder pain that comes on for unknown reasons and lingers for several months, but hurts in a specific area in response to known and predictable factors.
Neck pain that started after a rear-end car accident and hurts in specific places, but is influenced by a multitude of factors including movement, stress, sleep, and diet.
An ankle sprain that starts with an isolated incident, hurts in a specific location, and has clear aggravating and easing factors, only to evolve into a more complex presentation where the pain spreads, moves, switches ankles, or hurts on both ankles in response to unknown factors. After more time, it settles back into a more simple pain presentation before going away.
It is very common for things to fall somewhere in the middle, and knowing where we fall on the pain spectrum is quite helpful when it comes to management.
Pain Management:**
The importance of understanding the pain spectrum lies in both our expectations and management strategies.
One of the biggest sources of mismanagement of pain is treating complex pain like simple pain. This is likely due to many factors, chief among them being the fact that the scientific community has only recently begun to understand complex pain, and the integration of this new understanding into medicine always comes with considerable lag time. As a result, most pain management strategies treat all pain as simple pain.
And when it comes to simple pain, management is pretty, well… simple (as we will discuss).
But all pain isn’t simple pain.
There are millions of people right now whose pain presentation is not simple at all. Many of these people will spend a lot of time, energy, and money searching for the one cause/source of the pain and the one treatment that will fix their pain, only to wind up disappointed when this doesn’t come to pass. They will be seen by many care providers who are trying to do the exact same thing and will also wind up disappointed or frustrated when this doesn’t come to pass.
While a single cause/source of pain and likewise a single treatment is sometimes able to be found for simple pain, when it comes to complex pain, this is unlikely to be found. More likely is that a multitude of factors can be identified and influenced by a multitude of interventions, gradually over time.
Let’s first talk about simple pain management, then we’ll get into complex pain.
Simple Pain Management
Management of simple pain tends to be fairly straightforward.
1. Awareness
Step 1 is to identify the factors that make the pain worse.
This is usually fairly clear. When we sprain our ankle, it’s usually fairly obvious that the pain gets worse when we put weight on the ankle (or when we do so for too long), and when we move it in certain directions (or when we push it too far in certain directions).
2. Relative Rest
The next step is to relatively rest it. This means doing less of what makes it worse, and more of what makes it better.
After a sprained ankle, walking your usual 45-minute morning route may make the pain worse. If so, you’d want to walk less and see what you can do without making it significantly worse.
The same is true for movement. After a sprained ankle, certain aspects of your morning stretch routine may make the pain worse. If so, you’d want to find out how much you can stretch the ankle without making the pain significantly worse.
The Activity Safety Meter can be useful to make sure you’re not overdoing it.
You may also find that when it is hurting ice helps, or maybe heat, or elevation, or your massage gun, or all of the above. So these may be things that you do several times per day in the early stages.
3. Rebuild
After you have identified what makes it worse and what makes it better, and have found ways to not overdo it, you’ll want to slowly build up your activities to your previous levels. This is a key phase that is often overlooked in pain management.
If after an ankle sprain, you can only walk 10 of your usual 45 minutes in the morning, you’ll want to gradually build that back up over time. Maybe you walk 10 minutes for a few days, and that goes OK. Then you walk 12 minutes for a few days, and that goes OK too. You can continue building up bit by bit until you return to your previous walking duration. The Goal Tracker can be helpful for tracking your progress during this building phase.
Similarly, you’ll want to gradually increase the vigor of your stretches that you'd been backing off of during the relative rest phase until both ankles are equally flexible again.
These 3 steps are important steps for simple pain management, and they also form the foundation of complex pain management.
Complex Pain Management
1. Awareness
Just like in step 1 of simple pain management, awareness is key. You need to determine at least some of the factors that influence the pain if you are to make any changes.
This is often made more difficult by the nature of complex pain. Recall that complex pain is influenced by many factors or appears unpredictable. This can be confusing and disheartening. We can feel as though we are at the mercy of the pain.
A simple way to start this process is by paying attention to what’s going on when the pain shows up or gets worse. And it’s important to look broadly at the entire context to discover some of these many factors.
Some things to pay attention to may include (but are not limited to):
What you’re doing (activity, movement, position)
How much you’re doing (duration, intensity)
How you’re feeling
How much sleep you’ve been getting
What you’re thinking about
What you’ve been eating
How much water you’ve been drinking
Who you’re with
Some helpful resources for this are using a pain journal, an activity tracker, a sleep tracker, and/or a diet/fluid tracker.
The benefit of these tools is that they give us perspective. Putting it down on paper allows us to zoom out and find general trends that we may not have been able to see if we just tried to remember everything.
2. Experimentation
Once we have noticed some trends or developed some hypotheses by paying attention, the next step is modifying these factors through experimentation.
Just as discussed above with simple pain management, modification of factors can yield essentially two distinct outcomes: Rest or Rebuilding. And we can proceed in a similar fashion as detailed in the simple pain management section above.
The nuance here is that complex pain may not always yield a clear stimulus-response relationship. Meaning, it may not always be clear or immediately obvious what the effects of our actions are.
While in cases of simple pain, the effects are often quite clear and immediate. You move your ankle too far, it hurts. You stop moving it, it stops hurting. You walk too far, it hurts. You stop walking, it hurts less.
But when it comes to complex pain, it’s not always so clear. You may make a change in activity levels, movement, sleep, or diet and may not see a change for several hours or days, or the changes may be subtle and somewhat inconsistent.
This is the importance of experimentation. You may need to try things out several times or in several different ways to learn how the relationship is.
This is also the importance of journaling. Just as in the awareness phase, keeping notes can be very helpful for zooming out, seeing the big picture, and noticing trends (e.g. with the pain journal, activity tracker, sleep tracker, and/or diet/fluid tracker), as well as for tracking your experiments (e.g. with the experiments log) and seeing progress toward your goals (e.g. with the goal tracker).
3. Balance
This may well be the most difficult and delicate task of all when it comes to complex pain management.
The balance that I am referring to here is the balance between searching for triggers/relief and accepting/allowing the pain.
Of course we want it to be gone. If we could snap our fingers and the pain would be gone, we would do it in a heartbeat. But as it has been here for some time, it will likely take some time for it to go.
Spending all of our time and energy searching for triggers or ways to get rid of the pain can take away from us enjoying our lives right now. This searching, while helpful at certain times, takes up a lot of our attention and tends to pull us into the future, away from what is happening right now.
Practicing skills like opening to pain, allowing it, being curious about it, and zooming in and out on it, allow us to be with pain with less reactivity. This can drastically improve our quality of life right now, which is most important. Similarly, and somewhat paradoxically, being with the pain without trying to change it can allow us to learn more from it, which can lead to greater insights about triggers and things that can help.
This is a delicate balance indeed.
There are many times while on a walk I will notice the pain, scan the context in search of triggers, and experiment with different strategies in an attempt to influence the pain.
There are many times while on a walk I will notice the pain, and simply allow the pain to be there while I talk with my wife, look around, or feel the grass under my feet.
Many times I flow from one to the other throughout the walk. Seeking, allowing, seeking, allowing.
Not Better or Worse
There is no clear understanding of why some people experience more complex pain and some people experience more simple pain. But one thing is clear: one type of pain isn’t better or worse.
Experiencing more complex pain does not make you a bad or defective person, nor does it mean that you are wrong or have done anything wrong. Millions of people in the U.S. (and more worldwide) experience complex pain every year (4). You are not alone.
My experience with a more complex pain presentation is one of many facets. While I generally don’t like the pain and would prefer that it not be there, I have (and continue to) learned and gained a lot from it. It’s been both a secret source of shame for me (the PT who can’t even get rid of his own pain) as well as a source of gratitude. It has become a teacher; showing me when to slow down, sleep more, move more, take breaks, have fun, laugh; to move toward a state of safety and balance in my life.
And I have a similar relationship with my other sensitivities that may go along with the pain. Being sensitive to my own emotions and the emotions of others around me—while overwhelming at times—allows me to be better able to connect with people and learn about myself.
So if you are experiencing complex pain and in any way feel that there is something wrong with you, I hope that this article, if nothing else, lets you know that you are not wrong, bad, defective, or alone.
And maybe, through awareness, understanding, and a good dose of self-compassion, more of us with complex pain can come to a place in which the pain isn’t the enemy, but is rather a teacher or a guide, showing us how to live with more awareness, curiosity, experimentation, and balance.
Good luck out there,
Andrew
Footnotes:
*Footnote 1: Simple Pain and Complex Pain are terms that I invented to describe and condense three mechanistic classifications of pain into one spectrum. For further reading, see references 1-3.
**Footnote 2: Proper management of any pain state that is unclear, odd, severe, not improving, or worsening includes ruling out dangerous pathology by a licensed medical provider.
References:
Smart, K. M., Blake, C., Staines, A., Thacker, M., & Doody, C. (2012). Mechanisms-based classifications of musculoskeletal pain: part 1 of 3: symptoms and signs of central sensitisation in patients with low back (±leg) pain. Manual therapy, 17(4), 336-344.
Smart, K. M., Blake, C., Staines, A., Thacker, M., & Doody, C. (2012). Mechanisms-based classifications of musculoskeletal pain: part 2 of 3: symptoms and signs of peripheral neuropathic pain in patients with low back (±leg) pain. Manual therapy, 17(4), 345-351.
Smart, K. M., Blake, C., Staines, A., Thacker, M., & Doody, C. (2012). Mechanisms-based classifications of musculoskeletal pain: part 3 of 3: symptoms and signs of nociceptive pain in patients with low back (±leg) pain. Manual therapy, 17(4), 352-357.
Nahin RL, Feinberg T, Kapos FP, Terman GW. Estimated Rates of Incident and Persistent Chronic Pain Among US Adults, 2019-2020. JAMA Netw Open. 2023. doi: 10.1001/jamanetworkopen.2023.13563