I was just hanging out on my bed scrolling through my phone when out of nowhere I got this sharp stabbing pain right in the center of my chest. It would come for a few seconds, disappear, and then come back again, this happened on and off for about 3 minutes. I tried lying down but it didn't really help, and finally, when I sat up again it went away, but now I'm just left really freaked out. What could that have been? Should I be worried? No other symptoms though.