It sounds verry difficult. i can see why it would be very distracting for you... especially at work. i am sorry you are going through that right now.
i often hear music when all is quiet. i used to think my son had his music up. However, he has since moved out and it is still happening. i also used to think i was the only one who deals with this. i am grateful that i am no alone, however, at the same time, i am also sorry that this happens to others.
i don't find it particularly annoying most of the time. i have written the notes down a few times and that helped. For me unfortunately, i have never had lyrics flowing when the music is. For me personally, i think my tinnitus is a bit more annoying than the music right now. It interrupts the music with the sounds of a droning idling semi mixed with locust.
Have you tried to write the notes or lyrics down? Maybe having another music going on in earbuds could interrupt it. Is it a song you have heard before? If not, it might be your personal song. i believe we all have a song somewhere within us. Maybe yours is trying to show you something important. i know that sounds a bit far fetched. i am just brainstorming ideas.
i do hope the music can be stopped, or at least turned down enough that it isn't so difficult.