Hi tinylily and wallaby thank you for responding.
The last time I took him out on trail was at my old stables last summer. The only hill that we had to encounter was at the gate entrance leading down to the trail. Going out of the stables *downhill* he was ok, he just took his time slowly going down the hill. But on the way back if I were to use the same I entered he would act like this, and mind you out on trail he did far worse than what he's doing now, even on a flat path like a dirt road, it didn't seem to matter to him weather we were in a Euclayptus forest, dry riverbed, or dirt path. As soon as we were headed in the direction towards home, he would snort, paw, rear, buck, kick out, and grab the bit, lock his jaw and walk backwards as fast as he could. When we went out on trail we almost went down the side of a hill, landed in a dried up riverbed, backed up into a tree, and even a house. I had gone out alone, with riders, even had one lady circle her horse around mine to try to get him to go forward, had someone on the ground grab on to his bridle and try to make him walk forward. But nothing would work, so I would always just have to hop off and walk back to the barn with a psycho horse. So I just stopped going all together after giving up.
But like going out yesterday to the arenas he was perfectly fine and perfectly quite riding. Out on trail he would act like a seasoned trail horse until he realized we were heading home. I even tried tricking him a few times and would head back at different points on the trail but that didn't work either.
So I could see if going down hill with a rider, and possibly saddle issues would hurt one, his back, and two his legs because he would be anticipating the pain and would therefore react in anticipation. But last when I would have him go down the hill to the trail entrance, he acted fine, though it has been a year so I don't know if his arthritis has further inflamed since then.