I had been training for a marathon and was noticing after each long run (26km+) I was getting a strange feeling in my chest when I was in certain awkward positions, but quickly went away. After each run it was getting worse (even after 5km...) and this sensation was not going away. For about a month after this, while walking (I have stopped running for now) this sensation, in which my chest perhaps feels heavy, and almost like something is displaced frequently occurs, and is still ongoing. I am also having to breath deeper often than usual (but I have not been breathless/ wheezing etc..) and also importantly I have had no pain in the chest at all, just this "weird" feeling.
I thought it could be angina, but as I am only 19 (although eat quite a bit of junk from time to time ) and am expereincing no pain whilst exercising this would seem unlikely. I have had a ECG, chest X ray, and echocardiogram done, and the results from both came back as fine. My blood pressure is a tad above normal, but my doctor has put this down to white collar syndrome, as it fell substantially after the 2nd test.
Sorry about the waffle, just wondering what on earth this could be!?