Music playing in head 24/7

I have permanent earworms. There is literally never a time I don't have a song stuck in my head. The music is so clear that I sometimes forget I'm not listening to a song on an actual ipod. It plays at a semi-low volume in comparison to a real song, but it's loud enough that I hear it clearly even when conversing with people or when drying my hair with a blow dryer. Is this OCD related? It's usually not a problem, but my therapist has been trying to get me to meditate and the music in my head makes it nearly impossible.

I also notice that I tend to listen to the same cluster of songs for many months (sometimes a year) in a row before I change it up. The songs I hear in my head are usually a part of this cluster, but not always. I also wake up with a new song in my head everyday. Anyone else experience this?

I used to hear audibly theme music when I was young. My OCD has taken on different symptoms since I've gotten older.