i hit walls with my bare hands ..will it cause any harm ?!

When you get old they will hurt all the time.. Why not act like you have good sense and get a punching bag.. Hitting walls really does not impress anyone.. Makes you look a bit dense.. Not trying to be mean. Just know what it's like at your age and remember stupid things I did that I regret.. Is there anything that anyone could say that would make you think better of ruining your hands..

aside from the immediate pain, it will make the bones all weird and your hands may never work right if you keep it up. at least wear some padding on your knuckles.

Yes. You could easily break your knuckles, your fingers or the bones in your hands or wrists doing this. Stop it.

no unless you hit a stud