I read a book once called, "The Language Of Pain."
I don't remember who wrote it.
But, it got into the various ways in which people of all ages, cultures, genders, generations show pain and how they COPE with pain. It also got into how animals deal with pain and how they show they are in pain. Growing up on the farm, we doctored many of our own animals the best we could, unless we really needed the vet to come out to our house. But each type of animal deals with their pain a certain way and gives off signals. Same as looking for symptoms of them being sick.
Newborn babies have their own pain signals. The elderly do too. Those with dementia don't always verbalize their pain, but show it in different ways such as becoming agitated or restless.
Some people are stoic when in pain. Some are quiet and want to be alone and "turn inside"/within. It's actually quite fascinating. Some people get nauseated when in pain. Everyone is different.
Yes, take her in for a good check up if you can, but when you or your BF go with her, try not to speak FOR her. Let her do the talking.