Hi. Masturbation is cons8dered healthy until it starts affecting hour life and daily routine. Every young male goes through this phase of getting addicted to pornography especially due to the lack of a partner. I am sure you will grow out of it or go about masturbation in controlled amounts when you get a partner for yourself. But if you still feel that it is proving to be a hinderance then please visit a psychiatrist who can help you. As for the shape of your body, other than surgery there is no other way to change the shape sir. You can go about cardio exercises and a few others to mildly bulk up, but nothing more as long as you are fit, you should not worry about anything else. Best wishes.