Songwriters may hear the melody but not clear enough to write the chords. I listen late at night to the words buzzing through my head but just as the mosquito evades the swat, the words evade the light of thought.
Chasing words so that the thoughts come out complete makes sleep difficult. Words are needed but when we cannot catch them to make our thoughts known to those around us, life is difficult.
Words drift down the river of my mind, swirling in the eddies of memory, the current keeps them just out of reach. Fishers have the patience to cast the line to make the catch; enough catches and a sentence appears, then a few more and a paragraph, and maybe even a theme and a thought worth sharing.
Writers are solitary people for the most part, but when they cannot catch the words they need, they seek out others and listen to the words so they can begin to again shape their own.