I totally understand. I get nervous when I have to see new docs, too. So many of them want to reinvent the wheel, subject us to more tests, and arrive at their own conclusions despite our diagnoses. I've had that happen and hate it. It's exhausting, time-consuming, and frustrating. And it feels like they don't believe us or our experiences.
But think positive. A pain management doc probably won't do that. I hope that he will understand your issues, have a plan and be a big help on your health care team!