My friend 43 yrs male has been experiencing heart attack like symptoms since a year and a half ago. He saw many dictors and did all tests (angiogram for heart, echocardiac,chest scanner, blood tests,head MRI,coloniscopie, endoscopie..all tests results showed all is ok and nothing is wrong with his heart.but he still feels daily sypmtoms as if he us getting an attack( heaviness and pressure in his chest,chest pain(not sharp),shortness if breath,and annoying feeling in his left arm.he has no family history if heart disease.all results show normal however he is experiencing like ge is having thr heart attack.please help and suggest what can this be? Wat more tests does he have to do? Can it be muscular?