Other sources have carried all or parts of this interview with George R.R. Martin, AKA the FKB AKA the Fantasy Kingdom Butcher, but this article from The Mary Sue gets to the writing heart of things:
GAME OF THRONES AUTHOR GEORGE R.R. MARTIN EXPERIENCES THE PAINS OF WRITING, JUST LIKE ALL OF US
by Jill Pantozzi
As a writer, I think I can safely say a lot of us put our favorite authors on a pedestal. We somehow manage to convince ourselves that just because they’re successful and prolific means they never suffer with self-doubt or writer’s block. That’s usually not the case. And now we know A Song of Ice and Fire writer George R.R. Martin is not except from the usual trials and tribulations.