Dropped head syndrome with neck pain?

My mom (age 78) with dementia was in the hospital last Friday with pneumonia. She was treated and released. However, on Saturday morning she wakes up and can't lift her head. And she's been crying in pain for a week now whenever she tries. I've searched the dropped head syndrome which seems to be rather common, but nothing is said about pain. And heating pads and tylenol are not helping. Has anyone had this happen? Thanks