Well thank you very much..

..you tiny little betablockers. I've been taking these for the past five days, and they really seem to be helping matters. I feel a lot better, but still not really problem free. I went to see another doctor after the bloodtest turned out negative (which was quite positive I think),and according to her my symptoms could match a myocarditis. The devastating truth is, there seems to be no foulproof method to rule it out. So all I can do for now is do nothing. I have another appointment with another cardiologist next tuesday. Till then I will start taking ibuprofen in case I might have the worst.
Wish you all the best and see you soon
Benja