You need to take her to a vet so that she can be checked and offered treatment. The pain in her ear could be caused by an infection or a certain disease, which needs to be diagnosed and medications prescribed for it to get well.
Could also be ear mites. They bury into the skin in the ear and cause it to become raw. You'll see allot of crust down in the ear and sometimes it works it way out. I was always told to wash it all out and put mineral oil in the deepest part of the ear...which will clog the poors and smoother the mites. But, I have found that the medicated mineral oil the vet has really kills them fast.