I was just trying to get some answers about my 7 year old standardbred.
Not too long ago I got the chiropractor out for him as he was sore and acting up.
She told me to give him a week off then do handheld exercises over trot poles.
I have been doing this for maybe 2 weeks and just started to ride.
I’m riding him bareback to see if the saddle was the cause but he still seems agitated when I ride him.
He will twitch like flies are on his body, he will paw at the ground, kick out or at his belly and just doesn’t listen to my commands, he avoids them by putting his head down, itch his body or smell the ground. I’m hoping someone can help me 
Several reasons a horse may act up in these situations.
If a horse has a sore back, bareback will make him feel it worse.
The rider’s weight will concentrate in a smaller spot than spread over the bottom of a saddle much bigger area.
Some horses don’t like at all the feel of a bareback rider.
If your horse is really sore backed, he should not be ridden until that is resolved.
If he is not sore any more and still reacts to a rider, maybe he anticipates the old pain to return?
I would maybe first have the vet re-evaluate your horse before starting to ride, be sure it is not still sore.
My TB mare hates being ridden bareback. She just refuses to do anything above a walk and will throw tiny bucks to get the message through. She is sensitive and my butt bones/tail bone on her back = no way, not happening.
Since you’re having saddle issues, I would try a good quality bareback pad and see what happens; then re-evaluate. Many horses will not be happy with a bad fitting saddle, and many others won’t like a bareback rider. But, if you use a good bareback pad and he is still uncomfortable, I’d keep looking for answers for the soreness.
Could be saddle fit, could be physical, could be the way you are riding…
