Oh, I think everyone has stories and main characters that refuse to speak to them, even after the author has been summoned. I pretty much just plow through and force them to tell their story (for example, if you're under contract and have a deadline) or you give them their space until they're ready to let you know what's going on (if you don't have a deadline or contract to fulfill). I had a few shorts pull this on me, but never a novel.

I also have the opposite problem: a story of character calling to me adamantly that I just don't have the time to sit down and write at the moment because of other projects. I have 2 such short stories doing that now, but I have to finish the current novel because its deadline is looming.