But any kind of lust is sin.
Is a Lust for God a sin? If we love something with all of our heart, mind, and spirit isn't this by definition lust?
1)a passionate or overmastering desire or craving,
2)ardent enthusiasm; zest; relish.
It's when we take this ardent enthusiasm; zest; relish, and apply it to anything/anyone besides God does lust become a sin. Without a true "lust" for God we cannot obey the "Greatest command"
Not according to scripture. But this like anything else can be bad for you socially/developmentally if taken
in large doses. alot of times sexual desire pushes us to do things we normally wouldn't. Like speak to that pretty girl (or even a not so pretty one) and ask her out on a date. To be social with people when our "comfort" zone would have us stay back in the shadows... In short if all you do is learn to love yourself, in the long run that's all you'll have. At the same time though, don't beat yourself up for masturbating if you should fall into it..
Like Saucy said, the only real sin is when we involve lust with our "self pleasure."