I know this post is a little old, but I figured I answer, or empathize. I have the same thing. Except it's not really the same song over and over. I don't hear made up music either, just songs that I know, or have heard at least once before. I learn music unusually quickly. I can hear a song a few times, and without even trying I'll know all the words, the beat drops, the high hats, the pauses for acapella, and all the little adlibs. I listen to hip hop, but I can do this with whatever kind of music I hear. Everyone says it's like I have a music library in my head. Whenever I listen to music with people of course they know the words to alot of the music, but they are astonished by how much I know. And how much detail I know about the song, not just the words. If someone played the first second or two of a song then hit pause, I would know exactly what it is, and could finish the whole thing without the music. I can rap an entire song to an instrumental and be right on point with amazing precision. I wish more than anything that I could put this to good use as a career in the music industry, but I cannot sing, and I'm a white female... lol
Be sure that you are not alone
Same things over here
it's just keep repeating repeating repeating ..........D*** it
Well, if you have heard or sung that particular music before, what can happen with an OCD brain is it repeats over and over in the head, creating a deeper and deeper groove in your brain. So like a skier where it is easy to go down the same track you did before instead of carving a new pathway, the brain is going down that same groove over and over. You might try to replace it with something else if it is too annoying, but if it is just what you say, it is much better than some OCD thinking at least!