I Was Wondering If I Should Be Worried About Something.

I was wondering if I should be worried about something. Just a few minutes ago, I was yawning and at the end of my yawn, it felt like my heart beat was either noticeable or was going to stop. I quickly stop yawning naturally, because it kind of spooked me.This same occurrence has happened a few times over the past week. I am a 20 year old male who has went to the doctor plenty of times over the past few months because of panic attacks related to my health/me worrying about my health. I have done multiple EKGs and I had a echocardiogram and stress test done a few weeks ago and every result came out perfectly fine and they said I was really well. Is what I'm experiencing normal and something I shouldn't be worry about, especially if recent tests have shown that my heart was healthy?