It could be testosterone, or some other kind of hormone that increaces sex drive. It's mainly just a part of puberty - guys in puberty get horny A LOT, I know that feeling
It'll subside once you get older and your hormones calm down.
There's no real downside to masturbating a lot as long as it doesn't interfere with things like school or making friends and no blood comes out (obviously
So yeah, there's no real problem with that. Go at it!