If my echocardiogram and chest xray were normal, does that mean my chest pains

aren't heart related? I have chronic lyme disease and I'm in a major flare, and I developed chest pain, left arm pain and left shoulder blade pain. I went to the ER and after laying there for a while the pain subsided a little. They did an EKG and a chest xray while the pain wasn't there and it was normal...but if there was a problem, could they have missed it, since the pain wasn't that intense at the time?

4 or 5 days later I had an echocardiogram, also while the pain wasn't there (it's so fickle how it comes and goes) and it came out normal too. Does the pain have to be there for the echocardiogram to find the problem?

I'm just wondering how things like myocarditis are diagnosed, and if I had a problem like that, if it'd show up even if I didn't have any pain during the test.

Thanks!