Indeed, as a Catholic I believe that masturbation is an inherent sin. Masturbation, homosexual acts, sodomy, bestiality, adultery...they're all in the same sinful camp. We regard Matrimony (marriage) as sacred, and thus see any sexual acts outside of marriage as gravely sinful. Sex should only be reserved for procreation and bonding, pleasure derives from these. Masturbation gives neither, it is simply a practise of quickly ''pleasuring'' one's self.
This view has been the same for the Church for almost 2000 years of its existence...once upon a time all Christians followed the same chastity laws of the Church but people have liberalised in regards to their needs and wants
However in order to help you identify with the issue at hand, I will provide the Protestant view:
The Bible does not explicitly state that masturbation is sinful. However Jesus said that by even by looking upon another individual lustfully, you have already committed adultery in your heart. Thus since masturbation generally involves fantasising about another person. That being said adultery only occurs when a married person commits a sexual act with someone other than their spouse...thus unless you're fantasising about a married person, masturbation is not an act of adultery.
Some Protestants still view masturbation as sinful, seeing it as a grave self-indulgence and sin of the flesh. However many liberal Protestants remain quite open to masturbation, stating that it lowers the likelihood of pre-marital sex and adultery. They also tend to support contraception and birth control, sadly they will then support abortion if the contraceptive fails.
Other than the Catholic view, there is no unified belief regarding masturbation. You are very welcome to accept the Church's view of masturbation, just like many conservative Protestants do.
I hope that my words have helped you. Please worship the Lord and follow His laws.