To dream that you hear a song, means that subconscious mind is sending you some important news. To know the meaning of the dream you must look into the lyrics of the song, because it will tell you more of what kind of message it was given to you. Sometimes people listen to music before they are going to sleep, in this case the lyrics of the song wouldnt give any meaning of the dream, because it is simply a reflection of your waking life.
Song dream meaning
Read more about dreaming of Song in other dream meanings interpretations.