A zillion years ago, I took a graduate comparative literature course entitled "Music and Literature." The professor was (back then) quite elderly and traditional (but brilliant, in my view). During a discussion, one student commented that he listened to a particular composition while reading one of the assigned texts (by Thomas de Quincey), and that the listening and the reading coincided effectively. The professor replied that he couldn't listen to music while reading because he would focus on one of the two media and the other would be a distraction. The older I get, the more valid this view becomes.

I believe that music is a powerful stimulus for writers, but (for me at least) the time to listen to music is before writing, not while writing.