Creative friends (coworkers, really) tell me that "the wall" is a very real thing and that to get through it, you simply must find a way to push through it, somehow. That sounds a hell of a lot like me getting over my inability to want to dig a ditch as a child.
My creative friends say that they switch projects or turn to another art, such as drawing if they are a writer, to force their imagination and creativity to stay on, while not banging their head on the same section of "the wall" and getting terribly burnt out. Others just switch projects within the same medium.
I'm not a creative person, so I can't say if what that have told me works for everyone (almost certainly not) but I can paraphrase what they summarized for me.