52F with chronic left flank and abdominal pain, IBS, and prior CT suggesting Nutcracker syndrome. What would you investigate next?

I am a 52 year old woman with diagnosed IBS and longstanding recurrent left flank and left sided abdominal pain, sometimes extending toward my back. More recently I have also experienced some left groin discomfort.

I have had an extensive medical and gastrointestinal workup, including multiple abdominal imaging studies and a colonoscopy within the past two years. I understand that IBS can cause significant abdominal symptoms, and I am not questioning that diagnosis. However, after dealing with these symptoms for so long, I am trying to make sure that everything I experience is not automatically attributed to IBS if there may be another contributing condition.

I recently revisited a 2019 CT of my abdomen and pelvis that was originally performed for gross hematuria. The report described narrowing of the left renal vein between the superior mesenteric artery and aorta, an approximately 3 mm interval, and prominent lumbar collateral vessels. The radiologist noted that these findings can be seen with Nutcracker syndrome.

I am not assuming that Nutcracker syndrome explains my symptoms. I genuinely do not know. I am simply trying to understand whether this finding deserves another look in light of my persistent left sided flank and abdominal pain and newer groin symptoms.
I am honestly at the point where I just want answers. I do not want to chase diagnoses or convince anyone that I have a particular condition. I want to understand what is happening in my body, what can reasonably be ruled out, and what I may simply need to learn to manage. If the answer ultimately is IBS, I can accept that. I just want to feel confident that other reasonable explanations have been appropriately considered.

For physicians familiar with these symptoms, I would greatly appreciate your thoughts:

Would the previous finding suggesting Nutcracker syndrome warrant reevaluation?

What type of specialist would be most appropriate to evaluate its clinical significance?

What testing or imaging is generally useful for determining whether left renal vein compression is actually causing symptoms?

Would the newer groin symptoms or intermittent leg symptoms change what you would investigate?

Is there anything else in this presentation that you would reasonably want ruled out before attributing the ongoing abdominal pain primarily to IBS?

I am continuing to work with my own physicians and have upcoming appointments. I am not asking anyone here to diagnose me. I am hoping for thoughtful medical perspectives about questions or avenues of investigation that may be worth discussing with my doctors.

Thank you for taking the time to read this.