Your symptoms sound much like mine 3 years ago, except i had infrequent nausea. Please ask your doctor to look into IMHMV, a rare condition that mimics IBD, but instead obstructs blood flow to the colon (called an ischemic event) I had emergency surgery when my colon perforated and ruptured in the sigmoid and descending colon (which is the left side, like yours). Luckily, I survived because I was already at the hospital. So gratefully, they gave me a colostomy, then an ileostomy when the first reversal surgery failed. It wasn't until Mayo Rochester took on my case 4 months later when they were able to diagnose the IMHMV. I had another successful reversal surgery at Mayo to remove the rest of the disease from my remaining colon and rectum. I'm doing really well now, even with my shortened colon! This condition often isn't discovered until after the colon suffers the ischemic event, which will be emergent in nature. Dr. Kristen Rumer at Mayo was my surgeon and has seen IMHMV in a few cases. She published a paper urging GI's to investigate IMHMV in their patients who have unusual symptoms that don't respond to treatment. I hope this helps you!!