No, this is not "medical." I've always had this. It just seems harder to work past the "suffering" in this part of my body. My upper body has always been weak, but I build muscle quickly, say, in my biceps, triceps, even my back, once I start lifting and doing other stuff. Given the fact that I am almost 59 and probably in the best shape of my life, I won't stress over this. I have plenty of other muscular/bone/injury issues that are on-going, that I can complain more about!