I have left chest pains in the heart region, it hurts when laughing or heavy breathing. my heartrate is 70bpm, i don't have any history of chest pains?

Unlikely cardiac: it is very unlikely to be cardiac at your age. It is more likely to be a strain, inflammation, or reflux. As long as you don't have a congenital heart problem, family history of weird heart stuff, or some other practice that would out your heart at risk, it's probably benign. If it is concerned, get checked, but don't stress yourself about your heart.