pounding and racing heart?!?

Hello! I'm a 16 year old female and I was diagnosed with SVT when I was 12 but had an abalation to fix it 7 months ago. Ever since that I've had an on and off pounding heart. Like it feel like someone is pinching me in the chest. It happens when I exercise, stand up, get excited or anxious. I've had all sorts of tests after my surgery and they've all come back fine. Ekg, event monitor, chest x rays, and bloodtests. I also get really bad palpitations when I jump or move around wrong.

I don't really know what to do about it. Its really uncomfortable and scary. I've been told by 2 cardiologists that my heart is fine and I'm not gonna die but I still feel like I might. My cousin who is a nurse thinks it might be hormones and my aunt who is GP thinks I'm just anxious because of what happened and I'm hypersensitive to anything that happens in my chest.

Does this happen to anyone? I've notice it happens during pms sometimes and throughout my period but I don't have an anemia. Should I be worried?