@Jumpehunter. That's how Gene is too! She is usually SO diligent and willing to learn, and oh so gentle. But yesterday, 'I' even felt that she was off.
I think you need to call in an outside trainer to assess. This sounds to be beyond your experience level. I also very much question a pain response if the bucking has just started up suddenly.
She is not passed my experience level, sorry. :P