Dogs eating grass is quite common. In fact, most experts believe it's a natural behavior. There are several reasons for this behavior ranging from boredom to digestion issues. One common cause - lack of fiber - can be tested by increasing fiber in your dog's diet and seeing if the behavior subsides. Most importantly, do not spray your lawn with any pesticides and make sure your dog is not eating grass that you are not confident is chemical-free.

Shaking the head can be a sign that your dog's ears are bothering her. Allergies and infections are two common causes for ear irritation. I would bring her to the vet and have them examine her.