What Is Pain?

At first glance, this seems like a simple question. We’ve all felt pain—sharp, dull, aching, searing. It’s unpleasant. It’s distressing. It’s ouch! But does defining pain actually matter? We all know what it feels like, and we all know one thing for sure: we don’t like it.

Because pain is an experience we desperately want to understand. It reminds us of what it felt like to not be in pain. And the moment we feel it, we instinctively search for answers: Why? What changed? Pain, in its own way, forces us to become philosophers—it compels us to listen to our bodies and search for meaning. Why does it hurt?

When it comes to chronic pain, however, the answers are far from simple. We assume that if something hurts, there must be a clear explanation—an injury, an abnormality, something tangible. Yet, when no clear cause is found, the pain only deepens. In many ways, not knowing why something hurts is worse than the pain itself.

This uncertainty is maddening. Patients often see countless doctors, undergo endless tests, and still walk away with no answers. The frustration grows—not just from the pain but from the medical community’s uncertainty. If even the experts can’t explain why we hurt, what hope do we have?

And so, pain stops being just a physical sensation. It becomes a question—one that lingers, haunts, and demands an answer:

To truly understand pain, we must redefine it. We must put words to an experience we thought we understood. But do we really? We must challenge our assumptions, strip away outdated definitions, and reconsider everything we believe about pain.

This is not just a medical or scientific task—it is a philosophical one. Pain forces us to question our very sense of reality. Perhaps, the reality of pain itself must be reexamined.

This is what we do when life throws us an unexpected challenge—when things stop making sense, when the world we understood no longer aligns with our experiences.

As a physician, I believe we need to rethink our conventional understanding of pain and allow science to guide us toward a clearer definition. Our journey must start here: with an accurate, meaningful explanation of what pain truly is.

If we define success and happiness solely by material wealth, disappointment is inevitable. Success and happiness require a well-grounded definition; otherwise, we chase illusions, only to end up discontent.

The same is true for pain—if we lack a clear definition, we risk misunderstanding it, leading to even greater suffering.

Life is paradoxical and mysterious. Pain is no exception.

As of July 2020, the International Association for the Study of Pain (IASP)—a leading organization in pain research—updated its official definition of pain:

This revision added a crucial phrase: “or resembling that associated with.”

To fully grasp modern pain science, we must unpack the significance of this phrase.

To resemble something means to look like or seem like something else. But how can pain look like or seem like something?

We all understand the pain of a cut, a broken bone, or a burn—these are obvious, tangible injuries. But what does it mean when we say pain can resemble tissue damage?

This idea is counterintuitive, even unsettling. It suggests that the pain we feel might not always stem from actual injury.

You might ask:

According to current science, the answer is—unfortunately—yes.

Pain that resembles an injury, without an actual structural issue, is far more common than most people realize.

In fact, when it comes to chronic low back pain, this occurs in 95% of cases.

Yes—and no.

Pain is in our head in the sense that the brain and nervous system determine how much pain we experience. But no, it’s not imaginary. This isn’t a trick of the mind—it’s a very real biological process.

Before we go any further, we must first accept a fundamental truth:

Pain can resemble tissue damage—even when no injury is present.

This concept is the foundation for understanding chronic pain. And with it, we can begin the journey of unraveling the mystery of pain—one that devastates so many lives.