Diverticulosis are small pockets in the colon. They are typically painless unles something gets stuck in them and then you develop diverticulitis. Now to confuse you, although diverticulosis is usually painless, there are times when it can predispose your colon to spasm as stool moves through.
If you have frequent bouts of diverticulitis, you may be a canidate for surgery.
However, if you donot have bouts of true diverticulitis (severe abdominal pain, perhaps bleeding, perhaps fever) and are just experiencing pain with bowel movements, you need to make it a priority to keep your bowels soft with the use of lots of fiber supplements (two-three doses a day).
GI-PA
I have the same thing happen to me but I also get spasms up and across my back. I'm waiting for a colonscopy now to see if it is caused by diverticuli. I also have pain that can last for weeks on my left side right at the ending of my ribs when I have this pain I burp pretty steady. Have had chest x-rays, abdominal ultrasound and barium swallow and nothing has been found so far. Good luck.