Hi, I ve had heart palpitation feelings on and off ever since late April. I am a 21ish year old male at 6 ft and about 155 lbs. I ve had (within the time since): 2 ekgs 2 blood tests an echocardiogram (but not a stress echo) heart monitor for an hour at the hospital multiple doctors listen to my heart And all of those came back normal. But I am still concerned because: I ve had some chest discomfort at times (very mild) in the past two days ( I am currently not feeling anything), and I ll still get strange feelings from time to time like fluttering, or beating hard, or sometimes a bit of shortness of breath feeling. And my left lung always seems a little constricted and perhaps even has a little bit of stuff in it, but nothing major. And that has been going on since before last summer (I got a chest xray and it was clear) I have no idea what to think. Please help, Neil