I ve had a slight tremor in my left breast today. I do have atrial fib. Have had some anxiety over a neighbor s health recently. But have had worse worries over the course of my history of A-fib, which I take coumadin for. The tremor seems to sort of act like a slight leak of air might, that is, not really constant, but when I m lying down, a bit regularly. Not painful. At first I thought it was some bug in the L pocket of my shirt. Not here now, tho.