Is it normal for people to hump thing or not. And should I stop or continue to things?

I am 15 years old now and I am a boy. I fantasy about girls when I hump things, and when ever I see something with , I picture it and my mind a start things like sheets or pillow. (Not ever stuff I feel like something) But I have been things for some years and I don't know if it normal, not normal or just natural. things feels good but it also feel like a problem like Im addicted to . ( Im not really sure) I been for long and I try to stop when I first did it because I thought it was some kind of weird thing but keep on going in-till now. I test myself if I can try not to hump thing for a along time and see if if the feeling would stop but the more I res est the more it felt that I needed to something if I though about or seen y stuff. ( The more I thought about it the more the felling slowly come) I don't know what to do, if it normal or not and if I should stop or continue not to hump things. What do you think about what I said now and if you know the answer tell me what should I do. I need an answer if you know what to do or what you did.