Okay, I am starting to get REALLY freaked out over this now. It's starting to happen regularly. It happened once yesterday and now once today. It usually only happens every now and then. I really can't explain the sensation, but it feels like your heart has jumped in your chest, and your chest feels really weird for about 5 seconds afterwards. I wasn't out of breath or anything like that, nor do I have pain, but this is really creeping me out.. I told my parents but they're saying it's nothing.. I'm really scared that I will have a heart attack.. I am 18, by the way.