The harm in porn (aside from its very real addictive quality) is that if you don't know any better so to speak, you can set an unrealistic expectation of what sex should be. That as I understand it leads to the lack of satisfaction from the real thing.

You have to understand that both parties in those films are being paid to embellish quite a bit on what they're doing, if that makes sense. I've even heard rumors that some of the "actors" are given drugs to "help" things along during production, but I can't validate that. You just need to understand you're being given a show, not what sex between two people who care for each other is.

That being said, I am not trying to say that sex with a partner isn't as good as "porn sex." On the contrary, I would think the emotional connection makes it better.

I would tell you to just relax. Masturbating isn't going to cause you any health effects unless you do it so often that it interferes with your normal life. Same with porn, for the most part, though you need to consider your partner's feelings in you viewing that.

I hope I was of some help.