Tightness in center of chest n left side under armpit near heart, burning in groin/legs n pain in back/lungs what could these symptoms b caused by?

Multiple causes: There is no age listed which could help a bit in differentiating cardiac pain from muscle ache. I think no matter what you should see a doctor get a chest x ray as well these can come from a number of causes. Of course heart pain but it could be inflammation around the heart, a pneumonia etc I would see a primary as well as a cardiologist.