Wait, there are people who have silence in their brain?!?!
I always, ALWAYS, literally ALWAYS!! have music in my brain. There is literally never a time where there is not a song playing in my head. Usually on any given day it's a small part of one song on a continuous loop (right now it's Love Club by Lorde). The same part, over and over and over.
I have other thoughts too that loop around, like of self harm, and I'm always having conversations with myself and with other people in my head (and out loud).