I am having similar issues. Been having mostly left side lower quadrant pain at night and some times right side in the late afternoon. I have explored And discovered issues along the path to figure it out. Dealing with pelvic prolapse, cirrhosis with portal hypertension and gastric ulcers. I am inclined to think it is gastric, perhaps related to changes in the lining of my gi tract. Not sure but trying to pursue that avenue for some answers at present time. Let us know if you get any further insight. Thank you.