Hi and welcome to Yorkie Talk
I'm from NE PA
They really have to get used to being groomed. Mine didn't like it at first and now she just knows she has to stand there nicely while I comb her and she doesn't mind it at all.
I started by just combing her while she was sitting on my lap and nice and calm or tired
. I'd do it a little each day and in a way that it was slow and comfortable. Her face took a little longer for her to get used to, so I used treats. I'd give her one to chew on while I has combing her head and when she was good I'd give her another one as a reward.
I think it's just something you have to do gradually everyday and they get used to as long as you make it a positive experience
I use a stainless steel, straight dog groomer's comb instead of a brush. What kind of brush are you using? It could be also that she doesn't like how it feels on her skin if it's a little "scratchy" or something.