I didn't notice anything in the pictures, but I can think of a few other things you can check.
- Have you ridden her bareback to make sure that tack fit isn't an issue?
- Has her feed changed recently? Is there more grain or spring grass in her diet? I don't know about your horse, but mine is wacko when she gets grain.
- Have you had her checked by a vet yet? They might find a source of pain that you couldn't have known about, such as ulcers.
- Is there anyone new handling your horse?
- Are there any new sources of stress in your horses life?
My horse recently had a similar problem so I know how you feel. What I learned, after a lot of trial and error, was that she had stomach ulcers. They caused her to be generally intolerant and angry which is very uncharacteristic for her. After treatment she was back to her normal self again and I was so relieved! If you want to do a test, try giving your horse free choice hay for a week or so and see if she improves. The vet can also do a gastroscopy but for us it wasn't necessary.
I hope this helped. Good luck!