I have also had a dream with a song. I play guitar so that probably has something do with it. I remembered the song and I learned how to play it on my guitar. I didn't think much of it tough. One day me and my friends were practicing and while we were taking a break I played it and they said "whose song is that?" I told them it came to me in a dream. They said it was great. I still remember the song. I haven't had any more musical dreams like that one anymore.