I think that it is better is a good sign. I'm glad you went to the doctor about it previously. It's my understanding that pericarditis is typically mild in general. It's good you had an EKG which is one of the diagnostic tests that detect it. Even when mild. But, of course, tests are not infallible. There are other tests they sometimes do such as X rays, echocardiogram, MRI, etc. However, most of the time, pericdarditis goes away on its own or as you said, treated successfully to reduce the inflammation with things like advil. There are other 'big gun' meds they use to reduce inflammation in the body such as Mitigare. They can do more invasive things for more serious situations. But I think you are on the right track with your thinking. It starts to get worse again, I'd go back to your doctor. https://www.mayoclinic.org/diseases-conditions/pericarditis/diagnosis-treatment/drc-20352514