It goes without saying that the most imporatne thing is to determine what is causing your granddaughter to be uncomfortable. You might ask her parents to speak with her pediatrician to see if he/she can shed some light on what might be prompting the discomfort.
My older son was like that around 9 months. He was fussing because he was teething, and he was extremely picky with the food.
In fact, he is 2 years old now, and he still prefers drinking milk instead of any solid food. We usually have to deprive him of milk for a while before he caves in and eats something else.
Get that ear infection taken care of, and that will alleviate the problem.
Good luck, and don't worry too much.