Not meaning to attack or disparage anyone here, but…
I contend that no one can truly multitask. Perhaps some can switch back and forth very rapidly. I believe that if someone is talking to you, it behooves you to listen to him or her with all the attention that you can muster. If you are listening to music while writing, you are not listening to the music, (or writing) with all your will. You can play music while thinking of a beautiful butterfly, but the music is made largely by muscle memory and full creative expression is waylaid. This might just be this foggy fogyism on my part.