I'd say the primary bad thing about pain is not that it hurts, but that it's pushy and won't tune out. You could learn to sleep in a ship's engine room, but a mere stubbed toe grabs and holds your attention.

That, I think we could delete with impunity.

If we could learn to simply get along with any level of pain... how would it constitute an obstacle?

Real accomplishment requires real obstacles to avoid, remove, or transcend. Real obstacles require real consequences. And real consequences require pain.