Writing is different from wanting to write. Writing is sometimes figuring it out as you go. It took me awhile to accept this-- that I didn't necessarily have to, and actually couldn't, figure out everything perfectly in my head before committing it to the written word.
That's not to say I think every thought needs to be published unedited. But there are probably a number of us who think a lot-- a LOT-- about our writing more than we allow ourselves the delicious freedom of just doing it.
This is an issue when one is trying to finish challenges like NaNoWriMo or NaBloPoMo. Or, you know, writing for the pleasure of making something beautiful in the world.
Because to get to the beautiful, or the profound, it might be necessary to muse on the banal, to write a lot of ordinary stuff. Again, it doesn't all need to be published, but it all does need to be typed or put on paper. There's only one way from here to there, where "there" means writing words that express something meaningful to me.
And that way is the physical practice of writing. Not just luxuriating in the details of a scene or story or observation in the imagination, but practicing what it's like to put those thoughts into words organized into sentences, and then edit to make those sentences sing the imagined details.
So keep humming, keep jotting, keep imagining. Keep writing.