I think you're misunderstanding. He doesn't mean suffering in the sense that "bad things must happen to me before I have something to write about". He means tha

I think you're misunderstanding. He doesn't mean suffering in the sense that "bad things must happen to me before I have something to write about". He means that the act of creating something from nothing is in itself a difficult process in which the creator 'suffers'. You can rarely just create something easily out of thin air. Most of the time you have to put in a significant amount of effort and feel repeated frustrations before you write something good. This seems clear from the second and third parts of the sentence (after the first and second commas).