Pain is defined by the International Association for the Study of Pain as:
“An unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage or disease.”
So… what does that actually mean?
In plain English: pain is personal.
Pain is subjective — meaning no two people experience it the same way. For some people, a paper cut might feel unbearable. For others, it barely registers as an inconvenience. Pain intensity depends on the individual’s experience, history, and perception.
But here’s the part most people don’t realize:
Pain is for protection.
Pain is not always a signal that something is damaged. Instead, it is a warning signal of possible danger. Pain is your body’s way of getting your attention so you take action. That might mean you stop moving a certain way, change positions, or seek medical help.
Think of pain like a smoke alarm.
A smoke alarm is designed to protect you from danger. But sometimes it goes off when there’s no fire… it might just burnt toast.
Pain can work the same way.
Understanding Pain Comes From the Brain
Leading pain scientist Lorimer Moseley famously says:
“Pain is an illusion.”
That doesn’t mean pain isn’t real. It means pain is produced by the brain, not directly by injured tissues.
For example.
Imagine you’re walking, trip over your shoelaces, fall, and break your ankle.
Immediately, receptors in your ankle send signals through your nervous system and up your spinal cord to the brain. The brain receives these messages and evaluates what happened. It compares the information to past experiences, memories, and other sensory input.
Then the brain makes a decision:
Is this dangerous enough to produce pain?
If the answer is yes, the brain creates pain in order to protect you.
Pain is always an output of the brain for the purpose of protection.
It is the brain’s opinion about what is happening in your body.
And sometimes that opinion can be wrong.
Pain can be created even when there is no damage or disease present.
How the Brain Can Create Pain
Researchers have demonstrated how powerful the brain is in producing pain.
In one well-known experiment, participants were given a prosthetic arm that was positioned to look like it belonged to their body.
Researchers gently brushed a feather across the fake arm — and participants reported feeling tickling sensations.
Then the researchers poked the fake arm with a needle — and participants flinched in pain.
But the arm wasn’t real but the resulting pain was. Pain is always created in the brain and felt in the body.
So how did they feel pain?
Because visually, the brain believed the arm belonged to them. The brain perceived danger and created pain to protect it.
Once again:
Pain is always an output of the brain designed to protect you.
When Pain Persists
The challenge is that the longer pain sticks around, the better the brain becomes at producing it.
This is known as persistent pain.
When pain persists, two important changes occur:
1. The Brain Becomes More Sensitive
Over time, the brain requires less and less stimulation to produce pain.
Movements that used to feel normal may start to feel threatening.
Pain becomes easier to trigger.
2. Pain Becomes Less Precise
The brain contains networks that map the body. With persistent pain, these maps can become less accurate.
Pain may begin to spread.
You might notice:
- One knee hurts… then the other knee starts hurting
- A small spot in your lower back hurts… then the whole back feels painful
This does not necessarily mean your body is getting worse.
It often means your nervous system has become more sensitive.
So What Can We Do About It?
The good news is that persistent pain can be treated — and people do get better.
Understanding pain is the first step toward taking control of it.
In our next post, we’ll talk about:
- Modern treatments for persistent pain
- How movement helps recovery
- How the nervous system can be retrained
