Lower back, flank and abdominal pain (right side only)

38, female, no pre-existing conditions. 16 months post-partum.
Experiencing almost constant dull, achey pain mostly in the lower back, flank and abdominal. Sometimes the pain radiates into the glute and thigh and as high as the bottom of the rib cage. Right side only.
Have had blood work completed (3), urinalysis, ultrasound, transvaginal ultrasound, CT without contrast, CT with contrast (both unremarkable).
Pain started in January and fluctuates daily in varying degrees but is almost constantly there.
No other symptoms.
Currently on wait for an MRI (year waiting list) and referral to see a GI specialist (also a long wait).
Have kept track and there appears to be no correlation between foods, activities etc. and the pain.
Has anyone experienced this before? Ideas?
Thank you.