I could avg 15.0 mph on a recovery ride with an avg HR of 97-98.
Well, the good news is - your'e not dying!
You've got so much going on in this thread - not much use in commenting. So I guess I better comment.
Quit using a HR monitor, listen to your body and continue easy rides. Go to a doctor for an EKG, and then go to second doctor for s stress-EKG. And then start a new thread about what you learned.