Well after I posted that I looked up 'constant nervous feeling in upper chest' and a bunch of anxiety links popped up. There was mention that the feeling is a built up of adrenalin and exercise eats it up. So.. I just went for a run. I've been skiing like crazy this winter but haven't run since last fall. Well.. I felt like I could go forever. And I do feel better now. Hmmm... I could turn this negative into a positive? If this helps me get back into the habit of regular exercise... then maybe I should just keep at it.