I have a 13 year old Morgan cross gelding, he is about 15hh. He seems to be suffering from back pain. When saddling he pins his ears and throws his head up, when we tighten the cinch he tries to bit us. When I mount him he throws up his head and pins his ears once more, we work through the gaits and at the trot and canter he drops or pulls up his head with his ears pinned. He doesn't seem to show these signs after about a week of not riding. I have put up to 6 different saddles on him and even more pads, the pain seems to be mainly on the right side of his withers and under his belly where the cinch goes. If anyone can give me any advice on what to do it is welcome, thanks!