Hi. My mum had mixed dementia AD and VaD.
In time mums pain threshold became very low. What she would have shrugged off or not even thought of as being painful became agony . Mum was riddled with Arthritis so I ensured she had a paracetamol daily as prescribed. So I thought all was ok turned out it wasn't
.
Mum couldn't actually let us know she was in pain other than by crying or yelling , it turned out that some of her Sundowning was caused by pain.
Once on regular pain relief throughout the day my mum was a much happier bunny.
In time mum needed pain patches and I gave paracetamol during the day to deal with breakthrough pain.
IMO when a person like your mum is reacting as though she is in pain, it is real to her and most upsetting for you too.
Perhaps your mum has Arthritis and is not being given enough or any meds for pain.
I am glad you are ensuring a GP is called in.
We know our caree's much better than anyone else .
Personally I hate it when some professionals put everything down to Dementia .
Listen to your instincts