Thanks, everyone! I think you guys are right with the muscling issue though.
Idrivetrotters, Right now with it getting dark out earlier, I don't get off work early enough to work her and got all my barn chores done. I have been fostering her for about a month. The weekend is the only time that I get to really work with her. She is good and knows a lot about pressure/release. She is a nice little mare, very sweet, but has a headshy/tossing issue. I can just start hand walking her on the weekends. I have also just had her walk/jog, back up, change directions on the lead rope to see what she knows. She also let me rub her all over with a plastic bag and was okay with that as it was on the end of my little "carrot stick".
She is pretty skittish and spooky sometimes and other times she is fine. She is head shy and has a cloudy spot on her right eye. She also pretty much refuses to let me pick her hooves on her right side too. She has done some little rears while trying to pick up that right side. I know that is a dangerous situation. She lets me pick her left side fine. I think she might have had an injury to that side or arthritis. Who knows. I have mentioned it to the rescue owner what I have noticed.
They said she w/t through the auction at Camelot Horse Auction in NJ. I am a bit nervous getting on her with her having a head shy/tossing issue and she can half rear at this time. There is a girl that does some training and can ride her to feel her out. I would feel better working with her on the ground to get to know her personality a bit before I would feel confident to get on her.