Morwenna Phelps, the main character in Among Others by Jo Walton, uses a cane and has chronic pain.
From the author:
It’s 1979, she’s fifteen, she’s just saved the world from her evil mother at great cost, the world doesn’t know and doesn’t care and she has to go to boarding school. All she wants to do is read Ursula Le Guin and Samuel Delany and Poul Anderson and James Tiptree Jr and and and and… but her mother is still out there and so are the fairies.
UK publisher: Corsair (2012)
US publisher: Tor (2011)
Author represented by: Jack Byrne of Sternig and Byrne