What do you suggest if i am 18 yrs old years boy i have very weak body & i masturbate 2-3 times in the month what should i do to cure from it?

Get seen: You need a good relationship with a competent physician. Almost all your friends, including the best athletes, are enjoying their bodies much more often and this isn't making you weak. You need a health screen and unless you are seriously sick, you need guidance entering a culture of peers who exercise intensely and who are comfortable with their sexuality. You're a man now -- embrace it.