I also have music constantly in my head, but it’s something I’ve come to accept. As a musician, and someone going into a career in music, it’s not something that I will be able to control much. The only thing I worry about is if it is a song I hate. Then I purposely put another song in my head that I know well. It tends to overpower the other song, and before I know it, both are gone for a time.
The other thing is to remove your reaction to the music. If it annoys you, now it has power over you because you’re reacting. If it’s just background noise, it will have less effect. It might naturally go away over time.
I also view it as a positive thing. My brain finds very interesting connections sometimes. I’ll have one song in my head, and it will morph into another song. It’s usually a very odd mix of songs, so I spend some time figuring out why my brain associates the two. In that process I tend to learn something completely new. But, that’s more useful if you’re going to be a music producer and engineer like I am.