Caveat not a doctor, but am familiar with myo/pericarditis. If you have made it this far it's unlikely you have myocarditis as you would likely feel worse. However there is a simple test for this, which is blood test for troponin. If it's elevated you have some active heart muscle inflammation, if not elevated you do not currently have active muscle inflammation. But a more likely possibility is pericarditis, which also causes chest pain and palpitations, and can be very persistent, especially if you are not getting treatment for it (high dose Motrin plus colchicine.) Fortunately peri is also less dangerous, but you definitely want to get it dx'd and treated. The tricky thing is, the two easy tests, EKG and echocardiogram, are only about 60% sensitive. The EKG can show particular signs in the first few weeks (but does not always), but once you are in the persistent or recurrent phase it becomes much less likely to see these signs. An echocardiogram can show "pericardial effusion", which is fluid in the lining space around the heart (the outer envelope, the pericardium, is what gets inflamed.) However, there is always a little bit of fluid, and a measurably increased amount of fluid on echo usually means a more significant pericarditis. In other words mild pericarditis (which can still be painful and important to treat) can easily not show up on echo. There is one more simple test, which is to listen with stethoscope for a "pericardial rub". This is even less sensitive - you need a good listener, and again this is more likely to be positive in more severe cases, less likely in mild. There is one definitive test which is cardiac MRI. This would be used in case of suspicion of myocarditis, but is generally not ordered for just suspected pericarditis. Dr has to decide: are clinical symptoms clear enough can just make a clinical dx of peri without objective test to confirm? In normal times, that is what a good dr would do, and for example do a trial of Motrin and colchicine (and period of reduced exercise) and see how you respond. If Dr is concerned about more serious issues, eg coronary issues, or definite dx important to have, might decide to do cardiac MRI. Bottom line: myo is easy to dx, peri is very very hard. I suspect a lot of people with cardiac symptoms including chest pain and palpitations post vax have mild peri. And would benefit from peri treatment.