I'm about to throw my sucker in the sand with this one ?? 

I cannot seem to figure him out. It's like 2 totally different horses on each side. To the right he will get overly bendy in the neck and lose his butt, the only way I know how to describe it is "wonky". To the left he's definitely got a stiffer style but it's more smooth and snappy. I've decided to stop trying to fight his natural way of wanting to be stiff to the left because that just seems to be what works for him and he's efficient. I'm at a loss of what to do to the right (1st barrel). It's been suggested to put him in a mullen to straighten him up but I'm also nervous about how this would affect the other 2 turns ?? thoughts? Yes he is this way in dry work as well to the right. He's been vetted and has had all the "things" so pain is ruled out. 

EPM or bad stifles would be my guess. I know he's been vetted but I'd get a second opinion if he's had a fair amount of riding and isn't progressing.

Thanks Linda!

He just had his stifles injected. He was slightly positive in the stifles and very positive in the hocks. I guess I should give him a little more time to realize it doesn't hurt anymore but I'm afraid this is something he has always done even with previous owner and trainer she sent him to was unable to get it out of him. At this point I'm thinking I need to find a way to work with it the best I can instead of working against it. 

How is he just riding around? Does he ride around like gumby or stand up and lope around with his hip to the inside/shoulders up, rib cage inline, etc? Is this just around the barrel? 

A horse's left side really has nothing to do with the right side. You have to train each side independently.  Just because you have a horse working great to one side doesn't mean they can do the same thing with the other side. Think about thiss when you work on basics which you should every time you ride, do you work more to one side than the other?  If you have just started working on barrels, a horse can pick up things a lot better on one side than the other. It's never too late to work on basics. I have a horse that I raised that is 21. He knows how to run barrels. I work him on basics every time I ride. It keeps him listening to ME and keeps him sharp. 

Not just around a barrel, this is always. Stiff to the left, gumby to the right. I will say that I tried a mullen on him yesterday and he actually for the very first time stood up under himself to the right and i was able to take him from a large to small circle before he broke down into a trott. I don't have a lot of experience with Mullens so idk if this is something I should only work him in during the week and run in something else? I don't want to mess up his already stiffer left turns. 

He is being brought back from a suspensory surgery, both hinds. He should get the clear to make a pass through in 2 weeks. This whole time we've been working on these issues super slow. Been 4 months now. 

I bought him a couple years ago. He's a finished horse so he knows his job but I think he's just always gotten away with it. I was told hes always floated out at the first and even a trainer who i know knows what shes doing couldn't get it out of him. It throws me to the outside and sets us up horribly for 2nd. BUT his previous owner never did any kind of pain management or maintenance either. Hes 13. Now that I have all the pain things taken care of I'm hopeful it might make a difference? 

He naturally caries his head high. He's long and lanky and naturally stiff. Until we try those dang right circles.

I'll add that your probably right about riding one way more than the other. Before I really started to pay attention to this, I probably did do everything to the left more because it was more comfortable. 

If working in a mullen during the week, would you run in one as well? 

If he can't lope a small circle without breaking, he needs a lot of conditioning. I wouldn't be to concrened with the gumpy feel vs stiff feel if he actually has some collection and frame. Hip under him so he can drive. This is all just basics of getting a horse broke. If he can't hold himself in a 6' circle, he definatly couln't in a 3' circle. With the high head, I'm going to assume he's hollow in his back while riding which is leaving him strung out. This all sounds like just getting him broke to drive up in your heads and collect. Can you do forehand turns on him, two track? Finished or not, sounds like he just needs more broke in his body. 

Have you been seen by a chiro or osteopath yourself? I say this because I, myself, am tight in my right hip and lumbar area, and this translates into my riding. Just my 2 cents, but it's not always the horse. Have someone else hop on for a while and see what the horse does for them and if they have the same expierence.