I've been weight training for a couple of months now, lifting quite heavy (for me). I've developed a pain in my right upper arm - on the outside of the arm, sort of in the gap where the shoulder meets the tricep (not at the back). I can't trace back to a particular point when it happened bu it seems to hurt if I attempt a shoulder press. It also causes pain when i try certain stretching exercises (such as stretching tricep by lifting arm above head, bending at the elbow and pushing arm down behind head/back). It generally hurts when I move my arm about in certain positions. I occasionally get a dull ache in the spot too, outside of training. The pain seems quite centered on a small point right where my shoulder seems to end and my arm starts. Any ideas what it could be, or advice on recovery?