This could be an uncommon version of wry neck, although I've never seen it. I have had experience with some uncommon varieties of wry neck, and all respond well to vitamin E 400iu treatment. One gel cap directly in the beak each day until behavior is normal again for several days in a row. Give with a sliver of selenium. These can be bought at any pharmacy selling human vitamins.
Does she seem to have any balance issues? Is she limping or showing any leg weakness? Have you watched her at night to see if she's sleeping in an unusual position?