I think I keep getting gas pains in chest between breasts, 3 days. Saw dr last wk for physical if anything was bad would show in blood or ekg then?

Things can certainly. change quickly so a clean exam on Monday does not preclude the potential for disaster on Thursday. If the symptoms persist you should request a revaluation of your new symptoms even though you were just seen. Labs and EKG will not necessarily be predictive of impending issues.