Pain is part of the story of humankind.
Pain is affirmative of life, not destructive of it. Think of the scream of pain.
Pain is a vital molecule in a great, flowing river. Nothing moves in a stagnant pool, and you will not find pain there, only leering scum.
Pain is identical to brain activity. Pain is not one thing and brain activity another. It is one unitary movement. One pattern.
Whenever pain is separated from brain activity, a new philosophy results.