The character is female. She awakes in a world where she lives in a cave and it has either weird physics or weird geometry. She has to pretend not to be self-aware. She hears about a world where the rules are relaxed, and she starts working toward there. There's a world where she has to get bigger and smaller in order to move. That's about all I can remember.
Edit: I read it in an anthology. A few months ago. Some candidates include Dozier's Best of the Best, one of Strahan's "The Best SciFi and Fantasy of the Year" volumes, and The Wesleyan Anthology.