Server pain in rght armpit and elbow w/tingling down to distal forearm;atrophy in armpit, elbow, and thenar mscle of hand.

Pinched Nerve. Your description sounds like you have a pinched nerve until proven otherwise! with muscle atrophy compared to the opposite side i would get this checked by a spine or orthopedic doctors. You should expect to get imaging tests of your neck and possibly a nerve test.