My horse, Rio, was perfectly trained as a trail horse when I got him in March. We don't have many trails where I board him, so I mostly ride him in our outdoor arena, working on western pleasure, which isn't really all that fun, but its all we can do in the arena. Rio HATES IT. He loves to be out on the trail, like me, but there aren't any opportunities. He has mostly been a good sport when it comes to having to do work in the arena, but the past few days he wont canter. At all. I think it started when I was at the race track my barn has, just starting to canter him around, when he put his head down and started bucking. And then he did it another time about 10 minutes later. I just thought that I put his saddle on wrong, so I dismissed it as a once in a while ordeal. But a couple of days after that, he started acting up in the arena. I could mostly get him to canter when I put on spurs (which I never do), but today it was awful. He kept dropping his head like he was going to Buck, and pranced around when I tried to make him canter. I finally quit and went to lunge him in a round pen without a saddle or bridle. He was perfectly fine, besides being a little lazy.
Now for my question: does it seem like a saddle problem? I had purchased the old saddle when I half-leased a 20 year old mare named Maggie, and it fit her great. With my 10 year old fit horse, would the saddle suddenly get a little deformed so that it hurts him?