Burping, chest tightness, bloating, difficulty breathing for 5 straight days. is this a digestive or heart issue?

Hard to tell: Need further info. How long does pain last? Does physical activity provoke or exacerbate the pain? How old are you? Do you smoke? Does heart disease run in your family? These questions should be answered to a health care professional, probably sooner than later. Don't presume to know what your problem is before you can have a doctor or extender.