heart palbitations chest,arm,wrist pain

im a 20 year old female when i was younger around 9-10 i used to get very fast beating heart palbitations recently for the last two months ive been gettin stabbing chest pains on my left side as well as pain in my left arm, wrist and upper back. I dont get heart palbitations as often but i find myself short of breath and my heart beating faster than it normally should. every now and then I feel it skip a beat. I went to the doctors to get a eco 2 done on my heart but I feel this is to no help. Any suggestions on what i should do or what this may be? im very worried that i may have a serious problem