Pain means that there is a possible danger. We feel pain in our bodies because we may be damaging something.
An example: You are leaning against a hot stove. Before you realise it yourself, you have already taken your hand off the stove and you feel the pain of the heat from the stove. It will soon pass again.
The moment you put your hand on the stove, there are stimuli that travel from the hand to the brain. We call these 'danger stimuli' because they warn of danger. In the brain, the stimuli arrive at an alarm system. The alarm system decides whether the alarm goes off (what you feel like pain) or not.
The great thing is: you already feel pain before there is any damage. The alarm system works so fast that the pain prevents you from being damaged. The pain warns you.
When pain becomes chronic
In case of chronic, something strange happens. The alarm system is on all the time. The brain is convinced that there is a threat. But often the threat is long gone. The alarm system is confused and reacts over and over again.
It is therefore important to work on the alarm system itself.