I wonder that myself, when my back hurts I just punch it >_>. It hurts but I guess I get used to the additional pain that the initial feels like it's gone or something.
I once woke up with my neck kinda twisted and the pain was indescribable whenever I moved so I had to stand still and avoid moving my head. That ended up being impossible so I said "fuck it", took the pain and felt better the next day.