Masturbation is self indulgence therefore the sole person you feel guilt for is yourself - the jury is out, there is no self guilt in masturbation.
Kouji - mastrubation is normal. At your age, the only ways to get rid of excess sperm (if you don't have wet dreams and a regular sex partner) is to masturbate. Everyone does it, so enjoy.
Kouji: I don't have any easy answer, except to say that I can relate very strongly. It was weird in that I started out being fine with masturbation, but then because my peer group in middle school and high school was so fixated on it being something that was gross and obscene, over time I really started to struggle with it. Then freshman year of college it sort of got blown out of proportion in my mind because I decided somehow that I was mature now and I should have better control of myself than to have to masturbate regularly, and so I just felt all that much more guilt. I think there's no quick answer. I needed to hear from friends with whom I was particularly close that it really was okay. And I had to accept it for myself. It took a while, but I eventually realized not only that I didn't feel bad about doing it (why should I? I have no religious issue with it, I think it's a great thing to do for healthy, emotional release, appreciation of one's body), but that I could enjoy it a lot more than I ever had. Early on I masturbated simply to get to an orgasm, and I'd never really appreciated how good it feels all throughout the whole process! So I doubt this gives you an answer, but you should know that you're not the only one to feel guilty about it. I'd suggest trying to figure out what about it bothers you, try to understand why you feel guilty. Then you can try to reconsider how you view it. Wishing you the best of luck.
grow up. I'm not saying that in a mean way, but that's how you get over guilt. you grow up. Everybody does it. It's fun. It's healthy. Enjoy yourself.