Vision: Singing a song: right now you are at peace and happy. Hearing a choir: many meaningful hours ahead. Hearing or singing a happy song: expect good news. Hearing a sad song: bad news. Singing a sad song: you’re melancholy and you worry too much.
Depth Psychology: Singing means that you are at peace with yourself and the world around you.
A song in a dream: you are remembering past experiences and emotions. Was the song sad or happy? See Music, Song, Yodeling.... Dreamers Dictionary