idk she may be in out in her hips... but I just got her worked on about 2 weeks ago.. am I goin to have to keep gettin her worked on everytime she acts up.... that's goin to be more of a hassel than anything.
Horses are not a convenience. It is our duty
to make sure they are comfortable and pain-free if we are going to ask them to perform and work for us
on the barrels. If you don't fix whatever the problem is, it is only going to get worse. And she could also learn to hate the barrels, because it causes her pain. Would you want to do something that hurts? Of course not.
So it may be a "hassel" to you, but it is important to your horse. How else is she supposed to tell you she is in pain, except behaviorally? She can't talk to you so she is doing the only thing she can.
I am assuming you had a chiro work on her hips. Did he/she check the rest of her body?
Have you had the vet out? Maybe it's not a back problem; maybe it's something else.
Have you had the dentist out? Maybe she has issues with her teeth on one side of her mouth that is affected when you ask her to turn that first barrel.
Does she have any feet issues? Has the farrier checked her for any tenderness or balance issues?
Just because she doesn't do it at home, does not mean that she is not in pain. (As someone else already pointed out.)
If she truly is not in pain after you have ruled everything out, then
you can treat it as a behavior issue. But you always need to assume it is pain until you can prove it is not. Because again, horses can't talk to us and tell us what is wrong. We have to find it.