Could be she has developed swallowing issues. First you feel like you're getting stuff lodged in your throat when you really aren't, then later, you start to choke, always need water. Can't you ask her? get a nod or a shake for an answer??

Could be dystonia, jaw is one of the areas that's quite often affected.

Could also be she's trying to tell you something (sorry, I'm assuming she doesn't normally communicate any more just because you're here, asking this question...if she can communicate, obviously you'd ask her what the problem is...)

That’s tough. She is trying to tell you something. Maybe she can tell you when she is not refusing the food or meds. Take away some of the confrontation.