Rode my gelding last night and he was fine. Spent a ton of time grooming him today, and he was fine in the cross ties. Then I bridled him and started riding. He started shaking his head like something was bugging his face. He started to do it more and more, and I noticed his right ear was kind of cocked off to the side. I took his bridle off and put on his halter, thinking maybe something was pinching or pressing on something under the poll of the bridle. Nope. Same thing continued after I put the halter on.
He let me touch his ear, and didn't seem too impressed if I rubbed it for him, not bothered, but I wasn't providing relief. The ear stayed a little cocked. He can move it around, so it's not "stuck" that way. I turned him back out and he was rubbing his ear on his leg, and shaking his head again. He's eating fine, and having a great day otherwise (evidenced by his nice roll in the mud after making him halfway presentable.) I checked on him a couple more times before I left the barn, and he was at the round bale, ear was still a little cocked, but not shaking his head that I can see.
Any idea what can be going on?