Hi, I have been having tiny flutters on the left side, not on the chest but closer to the armpit, on the upper side of my left breast . I am female, 61 years old. I work-out regularly in the gym combining cardio and strength training. The fluttering started about two weeks ago after I did a 27-minute 3km run. I ve been having them since then. I have no other symptoms. I am not on any medication , only supplements . I drink wine or beer (2-3 bottles/glasses) about 2-3x a week. Doesn t bother me, but it feels weird. Is this something serious?