13 and Pains in the heart area?

Hi! So I'm 13 and I get these wierd stabbing/shooting pains in the outer left side of my upper chest, around the heart. The worst of the pain often doesen't last long and half the time a dull ache is left behind for about 20-30 seconds. The other half it stopa completely. Often the pain stays for a mintue or so, making it hard to breathe and I have to take short, shallow breaths and even they hurt. It's been going on for quite a while now, though it only happens once or twice a day at the most. At the least, once a week. It's getting really annoying now and I want to know is there something wrong with my heart? I don't know about my family's medical history but I'm sure there is no heart related issues. I don't smoke and I don't drink (except for when someone's having a blue WKD where my mum lets me have a sip, but thats once every blue moon). I have been going through quite alot of stress (I would say lately, but it's pretty much always been like this) so it might be because of that.

Please can someone help me? Thanks!