What you describe is how I have felt after a couple of rides where my heart rate was pretty high, probably 80-90% of max. The only other times I have felt this is after a stress echo test. This goes away in a day or two. I can't really describe the feeling in my chest that lingers, it's kind of like that exhiliration feeling you get after exercising, except it is really intense. Like I said, it goes away in a day or two and the doctor says its nothing to worry about. It should get better over a period of time as I continue to exercise.