[loyal_tree]

Have you checked her for parasites? Maybe she really does have an itch on her back and is desperately trying to scratch it!

I don't know the extent of it based on your description, sounds like maybe a neurological thing. Did it start suddenly? How long has this been going on?

Have you changed her to a different kind of bedding that might be causing a reaction? Anything near her cage that is toxic she might have come in contact with?

Is there something in her cage she could fall off of and possibly hit her head? Has she escaped from her cage and possibly had that happen?

I know that I am responding with questions instead of answers, because I can't say that I know why, but perhaps you can relate her behavior to a possible answer to one of my questions. You know your hamster the best and can disregard anything you know can't be it.