There's a difference between pornography and masturbation. You don't specify which sort of porn you're addicted to. If your post is serious and not trolling, then it's likely the addiction is to soft porn. (Hardcore porn addicts, people addicted to criminal filth, probably would be unlikely to post to /r/christianity.)

So if it's soft porn-- Putting all religious considerations aside, porn is dangerous because it misleads you about the degree of pleasure possible in a fallen world. This world is not paradise, but the point of porn is to mislead you into thinking that with enough orgasms from looking at enough beautiful women (assuming you're straight), eventually you will reach a point where you will exist forever in peace and happiness.

You won't. Because this is a fallen world. And your body, like all the porn stars, will age, become ugly, and die. And that's terrifying if you do not believe that this is only a temporary fallen world.

Good luck.