For me, it was my hip. I don't know what I ever did to offend it, but holy christ, it bothered me every day for years. I was in really good shape, too, but working way, way too much to get it looked at.

I finally did, and it never bothers me anymore. I think it was just tight back muscles pulling everything out from a decade of bush stomping and digging in rubber boots. Agony though. I really sympathize with anyone who's got any sort of joint pain.