I am 21 years old and i was addicted to masturbation for the last 5 years. i never had a nightfall and now i have stopped masturbation one month ago and still no nightfall occurred. is there any issue?

Normal masturbation doesn't cause damage. Likewise, normal sexual intercourse doesn't cause anatomic damage. That means using good technique, and as with all things in life, do everything in moderation. Even too much of a good thing can become a problem. Nocturnal emissions (wet dreams, nightfalls) or the lack thereof, in normal teens and college-aged guys, are not things that doctors worry about.