I’ve had an issue with a bigger arm pt then

Patient: I’ve had an issue with a bigger arm pt then the other . Very noticeable in size . Been like this for a while and I haven’t exactly stayed on it , just because I figured maybe not so proportion.. But it’s very sensitive, hurts pinch type and feels like a knot is in there from time to time . Besides the ones that are suppose to be in there .. I had a “hand breast exam and arm pit and nothing was found .. What could this be besides obvious cancer symptoms

Doctor: