Not painful at all, only a tingling or throbbing under left armpit. It is more pronounced since I am taking 100 mg Coenzyme Q10 for gum health. Should I stop taking this supplement for a week to see if these symptoms dissipate. I smoke 4-6 cigarettes a day but am otherwise exceptionally healthy 65 female with no history of heart problems in my family; 130 lbs and walk 10-15 miles a week. Lacto-ovo diet, no alcohol. other than a rare glass of wine.