I think they call it an ear worm and it does happen to most people if not everyone. Psychologists have reported in articles I've read that 90 percent of the population has a song get stuck in their head every couple of weeks. Why psychologists are the ones who report that, I don't know. But perhaps it is because people ask questions about it like you are. It's not mental illness. They are most prevalent when the mind is wandering which they say is about 40 percent of the day. I know yours are the actual song but the lyrics of the song. Things to try . . actually listen to the whole song in it's entirety, chew gum, engage in something. That might end the ear worm.
** which by the way, is this bugging you, infringing on your life or you are just wondering about it.
Now intrusive thoughts are a form of OCD, called existential ocd, obsessive thoughts and the compulsion is reassurance/checking. My son is diagnosed with this and we are about to begin ERP therapy for it. But that sounds very different than what you describe. Not like it at all, really.
and wanting things organized, neat and tidy and in specific ways is also not really ocd. Obsession followed by compulsion. I have a son who is a neat freak (hard to believe I'm his mother). My NON ocd son will organize anything you give him. Keeps everything in a place and just so. It's just kind of how he is. He likes it about himself. He actually has a mentor job in high school. Kids that that have difficulty organizing, he is assigned to in order to help them. ha. Too bad he has never tried to organize my kitchen!
I think it also may help you when thinking about these things to decide impact. Everyone has quirks, personality traits. For some, things could be SO much that it interferes with daily living. That's when you would start to take more notice of it. Other than that, it's just a quirk in your life.