Had a bilateral mastectomy in December for cancer prevention. Expected arm pain for a couple of weeks, but it\'s been 4 months and the right arm is fine, but have pain in left shoulder, loss in range of motion, general weakness in arm. Ligaments in shoulder feel \"soft\" as if shoulder COULD dislocate, but hasn\'t yet. Shooting pains down arm periodically. Starting today, shooting pains in bicep that cause my whole arm to go limp. Happens mostly when I am holding something with that hand, like a phone to my ear. Surgeon says it is coincidental to the surgery but not caused by it, but I never had any such problem before surgery. Just need to know if it is a nerve problem, a muscle or a joint problem. Who diagnoses and treats this kind of thing?