I love this quote from Vincent van Gogh

"I dream my painting and I paint my dream"

I think many songwriters do the same thing. 

Townes Van Zandt said this about his song If I Needed You.

"It came to me in a dream. I was living in Tennessee with Guy and Susanna Clark, and I was asleep, and I had a note pad by my mattress-I had a mattress on the floor. I was dreaming I was a folk singer, and this was the song I played, and I happened to wake up, write it down and went right back to sleep. The next morning I woke up, went to the room with all the guitars, picked up a guitar and played it through. It never has changed"

Wow! 

We can only hope for a dream as great as Townes. But I think we all pull song ideas from dreams. Night dreams and daydreams. Dreams are just our imagination wandering around brain town.

"Imagination is the highest from of research."

Albert Einstein

Keep that note pad handy!