Does diverticulosis and diverticulitis usually cause many symptoms?

No and yes: Diverticulosis (pockets in the wall of the colon) usually causes no symptoms. May be associated constipation/gas/cramps, but not specifically due to the pockets diverticulitis typical symptoms: pain, usually left lower abd, fever; associated with high WBC count. Urinary symptoms if inflammation affects bladder or ureters. Can recur. Not from plugging of pockets, but blow out of weak wall.

Depends: Diverticulosis typically does not cause any symptoms. Symptoms such as pain and fever occur when it becomes diverticulitis. Diverticulitis attacks can range from mild (treated on an outpatient basis with antibiotics) to severe and life-threatening (treated with emergency surgery, hospital admission and IV antibiotics).

Diverticulitis: Assuming you have diverticulosis in the first place, the symptoms of diverticulitis would include fever, chills, sweats, nausea, diarrhea and abdominal pains usually either in the lower left or lower right aspect. Diverticulitis comes from a ruptured diverticulum. Diverticulosis typically causes no symptoms.