What is this????

[Plushiesmakemehappy]

Hi guys, so today I have done a lot of activity. I had to bathe my dog which required me to chase a 60 pound puppy all around my yard several times to pick her up and bring her back to her little pool thing. So the last time I did this I was washing the soap off of her when suddenly my chest felt uncomfortable no pain though. But the more I got my breath the better it felt and it all went away. Then after that I worked out and it was pretty strenuous for a beginner like me. I got sweaty and everything was fine my heart rate went up as usual. But about 15 minutes ago I was on my computer playing a game when suddenly my heart felt like it was twisted for a second and went away. It went away and I broke out in a little sweat from panicking. It didn't hurt at all. About 4 months ago I had this feeling in my chest quite often and today was really the first day in a while that I did a strenuous work out. Is this ok? Am I ok? I had to go to the urgent care a few months ago for this same feeling and they did an EKG on me and it came back normal. I am only and 18 year old girl I don't wanna die or get heart surgery yet.