Is Pain Like a Muscle?

I think i have a high pain tolerance. I learn that as a swimmer. It very much becomes a mental thing, because your brain gives out long before the body. Still, when you're doing these big runs that really push you, you have to be living in so much pain. You can acclimate to it and your bench mark for tolerable verses intolerable will shift. There's a, there's a a endurance athlete named david goggins. Hespent on my podcass. He's personally inspiring to me. And he said something that's always stuck with him, which is that when you think you're done and you can't go any further, you