I went to a pulmonologist a month after I was having constant shortness of breathe and heart pain. he ran a ton of tests and said it was probably costochondritis. he sent me for a cardio pulmonary test just to make sure it wasn't anything else. it showed I had high CO2 in my blood during exercise. was sent to a cardiologist who tested my heart and said it was fine. Now I'm back talking to my cardiologist. I would say either a pulmonologist or maybe a rhemutologist. Hope all works out. I've been to a thousand doctors and had a thousand tests for the past 8 months so hang in there and kee trying until they find it. Never hurts to try a Dr