I'am 21 y old my problem is i can see my heart beating in my chest it beating normal not fast , is that normal, and i"m skinny my height is 185 cm and

PMI: Yes - what you're seeing is the PMI or Point of Maximum Impulse - the place where in very thin people you can see the heart beat. This is 'normal' and nothing to worry about. Symptoms I WOULD worry about include 'fluttering' of the heart, getting dizzy, passing out etc. Over time if you gain weight - you may not see this any more, although likely you can still feel it with your hand.