She had a barium x-ray but they said they didn't see anything but to the right of her throat it is still tender?? what is it?

Possibly sore throat: I assum,e from your question that you had a barium swallow which evaluates your esophagus in the neck. There are other structures in the neck: such as larynx(voice box) and lymph nodes. An inflamation in the throat or lymph node infection could cause pain as could a spine problem. Suggest you see your doctor as more information as to the type of pain and exact location required for intelligent dis