If you wanna write, then write. It is that easy and that hard.
Back in the day when I wrote for a living, I produced a ridiculous number of words every month. It was a job and really nothing magical, and I don't think I ever worried about it much. Granted, it wasn't fiction (unless you count dwelling over the various features of a product as such), but it was writing at a steady pace.
I believe many aspiring writers often confuse two different aspects of writing--there's the craftsmanship part where you simply produce words in approximately the right order, following a predetermined syntax, and there's the creative part where you decide what the words are about and where they lead. When the words aren't coming out the way they should, they tend to think it's the dreaded writer's block when it's actually nothing more than a problem with learning the basics.
This is not about anyone in particular, btw, just an observation.