Pain (n.) is not the problem but the withdrawal from withdrawal: the unwillingness to squirm, which, since it would stop us fleeing danger, is suicidal.
Pain (n.) is learned partly from parents: the child watches their sympathy, horror or disgust and learns resistances to make for himself.
Pain (n.) is inflamed by the struggle to escape it.
Pain (n.) thrives on the tension of trying to escape it; when the tension stops, mind and body absorb it as water absorbs a blow.
Pain (n.) and the effort to be rid of it are the same thing; wanting out of pain is the pain.
Pain (n.) seen as yourself stops being a motive, for there is no one left to be moved: it hurts — period.
Pain (n.) often seems our measure of reality — which is why believers in the unreality of matter have trouble convincing anyone pain is unreal.