Please Tell Me This Is Stress

Sometimes I will get little eletric shocks either under my left breast or above or right in the center where my heart is........ Sometimes I feel a pressure on my heart..... What could be causing this? It usually happens around night time sometimes during the day, like today I ran out to the car cuz it was raining and a shock of pain went through my heart.... Please tell me this could be from stress or anxiety?? Im only 17 , 18 in a few days I dont want to like die of a heart attack this soon