What could be wrong with me?stomach and heart pain

Yesterday night I had really bad heart/chest discomfort,as if there was a needle on my heart or something keeping it from beating normally,I felt the need to curl-up and then my stomach didn't stop growling till my mom gave me a warm gl of milk,it made it better,but then my lower stomach and sides were cramping so much,then it went to my shoulder.When I woke up today I was feeling great but right after eating my bowl of bran flakes and skim milk,my lower stomach and chest started cramping again.I don't have my period yet...I'm turning 14 in a few days and I've felt such discomfort since quite some time ago,it's just at hat it didn't last as long as now.I also often have "beating"pain in different parts of my body.