I Have Sharp Heart Pain In The Left Side

I am a 22 years old male, 6ft tall and 177 pounds. I been having this heart related problem or maybe something else that it's kind of hard to explain. The reason for that is because I don't feel it often, it usually happens once in like months or years. But when it happens I feel this pain in the heart area in the left side, one hand palm or little lower from the chest. This usually happens when I sleep in the left side and sometimes the right side, but when I sleep in my back I don't. The pain is kind of sharp and would continue for like 1 day or 2 and then it goes away when staying straight and sleeping in the back. I am not sure what could this be and I been doing some research to find out what this is. Any help is appreciated. Thank you.