Hi,
For several months now I have had discomfort under my left arm. Like, literally in my armpit area. This discomfort has been increasingly annoying, and now seems to be moving down the back of my arm. There is no swelling at all, and no lumps or bumps of any sort are present. Also there is no chest pain at all. I have full range of motion in my arm, though it is a bit uncomfortable to move around a lot. I just have this annoying discomfort under my arm. I'm wondering if this could be a strained pectoral muscle. I'm a generally healthy 42 year old male, and I had a physical exam 3 weeks ago which was fine. I mentioned this discomfort to my DR and once I told him there was no swelling/lumps he seemed rather unconcerned. I would however like to figure out what this is.

Any hints/feedback would be appreciated.

Ed