Have you ever had a jaw issue or TMJ when going to dental exam?

I've avoided dentist for years because my TMJ can be painful if I keep my mouth open wide or too long. On top of that, I have a misaligned jaw. I know I need a cavity filled so made an appointment. They assured me I can take breaks if I get an X-ray or if it's filled. I'm still really on edge. Anyone else go through this?