Its normal to have urges to want to masturbate throughout the day. Youre young and your hormones are fluxuating. Its normal to masturbate and look at pornography or other stimulating materials. when it becomes a problem is if you no longer get pleasure from it, but do it as a compulsive behavior, or if it interferes with your ability to lead a normal, productive life (for example, youd skip class to masturbate). I think what youre experiencing is probably in the realm of perfectly normal.