I HATE confrontation..help

I need to speak up to a chiropractor...shes been great so far in helping adjusting my jaw to be realigned. I clench at night, so last year it became misaligned with horrible symptoms, vertigo, fatigue... she began also doing adjustments to my back and neck. Im not sure Id be getting that done with a cranio -doc, if they realigned me. They use a splint type tool, like a guard. But the chiropractor was closer to me and a bit less money so went there.
The other day I had severe back pain from the tool they use on back. Lasted nearly two days. Thats never occurred. I would like to halt back treatments..I want mainly jaw focus. My back is aligned im sure, more than when I began last year. I dont think its vital to my jaw treatments to also do neck and back, but I feel they will say I should still do it. I get all nervous when disagreements begin. How can I be up front ?