Ooooops! Sorry - I didn't notice until after I posted that you are Tim's Maw....
So sorry no one has been able to offer you any advice, Tim. Evidently the only thing left for you to do is to return to your cardiologist and explain your pain to him and see what he suggests.
We can really only offer advice if we've had the same symptoms - and looks like we haven't.
Please take care of yourself and we sincerely hope that your problem can be resolved.
Best wishes