How to prepare for initial OBGYN appointment?

This is going to be long, so I apologize in advance!

I started having right-side abdominal and pelvic pain over two and a half years ago. We initially thought it was appendicitis, but all scans were clean. My PCP then thought the issue was constipation, but the pain has never fully gone away.

Other physical symptoms and irregular periods led me to a PCOS diagnosis a year ago, and I have been on varying doses of spironolactone since then. Some of my physical symptoms have improved, but my right-side abdominal and pelvic pain, as well as really terrible back pain before and during my period have not. I had an abdominal ultrasound this week to look for cysts, and my doctor described the results as “remarkably normal”. She then referred me to an OBGYN to explore possible endometriosis.

I have not seen this OBGYN before, but I know people who have, and they say she is open to hearing people out and performing any tests needed. I have spoken to her nurse twice, and she was able to get me in sooner than the receptionist, so I am cautiously hopeful for this appointment.

If you were in my shoes, what would you do to prep for this appointment? Should I ask for a transvaginal ultrasound or any other tests? Is there any outside literature or research I should read in the next three weeks to prepare?

Thank you!!