I agree. I don't think its pain, I think its that she thinks every time I go to her I am going to halter her up and ride/train her. And she is a "fatty" and loves her grass and doesnt like to be taken away from it. A while back she pinned her ears and turned her butt to me. I took her immediately tied her up so she couldnt eat and made her work. When she did it yesterday I told her to quit it and stuck with her hopfully showing her that just because you do that doesnt mean im going to give up. After awhile of being in the pasture just rubbing on her and letting her walk away and coming up to her again it seemed to improve. How would you fix the problem? She doesnt fully respect me yet(obviously)...still working on the training with that.. My friend said her horse did that to her when she started out, and after working with him and "loving" him before she haltered him, he learned it was ok.
As for her pinning her ears or turning her butt to you, I would change instantly from approaching with a nice guy attitude, to one of "don't you dare swing your butt at me" . I would drive that butt away firmly and quickly. She'll run away for a bit, but you just stand for a bit, then return to walking up to her. If she's good, go up and pet her and walk away a few times. If she pins her ears or turns her butt to you, drive her away! Being driven away will make her rethink being near you. I know it sounds wierd, but it works.