I completely agree! that is exactly the first thing that came to my mind; that he is in a 'pain' stance. HE is trying to rock back off of his front toes, I think. Additionally, his face also looks like an unhappy horse.
Conformationally, He is unusual. It's almost like he is 3 horses put together into one. His hind end is classic QH. (nice hip, good hock angle) His shoulder is light, and too upright, so not so well matched to the hind end, his neck is short, and relatively thick, and his head large and handsome but seems to belong to a third horse.
First you get with the horse, then you get the horse with you.