I often will listen to the same song for hours or days, sometimes even weeks. It's not like I listen only to that song for days - I will have to occasionally listen to songs for or from one of the bands I'm in, to prepare for practice, and I also will listen to other music when I am playing or practicing something else, or when teaching private bass or guitar lessons. I consider that different though, because it is special interest and work related.
I also will often listen to a song over and over, and sing along with it, and also play it myself over and over. I often will make my own version or versions of the song that differ from the original in various ways (I prefer doing my own rendition of covers to trying to carbon copy the original). I came up with my favorite rendition of John Coltrane's "Naima" during one of these "song binges" where I listen to a song over and over again.
I don't know if it's OCD - simply because I don't need to listen to it a certain number or anything, or until it "feels right" to stop like it does with my compulsive movements (that is, for both the number and the "feeling right" to stop). I don't even know if that stuff is OCD, I just know it seems OCD like, and they were much worse and much more numerous when I was younger. One of the key differences between that stuff and the repeat music listening, is that when I listen to the music I -want- to do it, but when I'm doing the compulsive stuff I always wish I didn't have to do that stuff - it can get tiring - when I'm doing it I'm thinking about not wanting to do it but needing to anyway.