Pain during exercise?

[Moonglo]

I have a bit of an issue with my right arm. There is a spot just below my right shoulder on my upper arm that seems to get sore pretty easily during exercise. It goes away when I finish exercising. I notice that this part of my arm looks like there might be more muscle there... or something. Its shape does not seem to fit the rest of the arm right now, and it does not match my left arm at all.

Has anyone else had experience with something similar to this? Does it sound like a problem, or could it be that my arm really is building muscle?

[Caravaggio]

From your description, it doesn't sound good. I suggest you check with a doctor or sports injury especialist.