mmm as Kristy said it could be pain, but because it was a ex racer its use to going left. I believe flatwork could fix that. When you are trying to turn- how do you ask? Ovibisally he needs help going right-so do as much as you can ie
leg, open the inside rein ect.
If he is a ex barrel racer they should not have any problem turning either way! That's if he was successful....... (not saying that he wasn't)
But first of all check for pain first, but theres not much that good hard work can't fix.