Horse in pain?!! HELP!!?

I don't think you need to panic yet! Just give her a couple days off and then try to work her again. Most likely, she'll be back to her normal self. She might have been in pain from the kick, or just having a bad day for whatever reason. If she's still acting weird after a few days off, then you can start spending money on vets and chiropractors. Sometimes a little time off is the best thing for them to heal.