What Causes Fluttering In The Chest, Heart Burn And Shortness Of Breath?

My son in law has been having attacks , where he c/o fluttery feeling in chest, heartburn , SOB. (First episode sent him to ER, as thought he was having a heart attack, which then everyone jumps to must be a panic attack ) He has been worked up by primary care, GI and Cardio ( EGD today was neg, as it was thought he was having esophageal spasms) EKG nl, scheduled for an ECHO next week. He is 28, usually good health, recently quit chewing. He is a highschool teacher, and wheat farmer. As a nurse, I have been very frustrated when he tells me of his visits with these doctors, as what he hears is tests normal, guess you ll just have to live with it They did start him on xanax BID, and a BP med. (easiest way to tell him a DX is anxiety attack! ,which I don t think it is) He is such a relaxed young man, intelligent, easy going, I just don t know what direction to send him. Any ideas?????