If I'm obsessed with masturbation, could I have ocd?

Too Much Good Thing? You might want to take a look what the "go ask alice" online q&a service run by columbia u's school of public health: http://bit.Ly/17krv3h. "alice" suggests questions to ask yourself about your patterns of masturbation, your attitudes about it, etc. She points out that different people have very different masturbation habits. There is a wide range of experience.
Possibly. If you have other symptoms of ocd, otherwise you may just be going through a phase. Or you find it so pleasant and so irresistible that you arethhinking about it all the time. Seek counselling if it is interfering with your life.
Very likely, yes. By definition OCD contains the word "obsessed". Generally when we say we are obsessed about something it's because we don't like a specific thought, feeling or behavior we have that contriols us and we don't control it. To rise to the level of a disorder it has to impact our life negatively, cause problems and appear to be out of our willful control. That's when professional help is needed.
Even if not..... Whether you are portnoy reborn or not doesn't matter. Ssris (such aa fluoxetine -prozac) are used with great effect to treat ocd. They also dampen libido and orgasms more difficult. That's the ticket! i doubt without frequency, we can tell if your ocd.