If everyone had their own personal background music, interpersonal relationships would be a lot easier. If you didn't like someone's music, you would know to avoid them. If a love song was playing, you would know what to do; heavy metal likewise. It is not unusual to have background music in dreams. We are used to having music on television or in a movie set the tone of a particular scene or character.
An interesting phenomenon is when you compose music in your dreams. It may be very telling regarding the emotions present in your dreams which, in turn, can help you decipher the meanings of the images.