Sharp intermittent low left inside back pain then diarrhea onset 24 hours ago does divrrticulitis cause sharp stabbing left rectal pain diarrhea

It could. You should be evaluated by a doctor if you have severe pain. There are other things that can cause these symptoms, although diverticulitis could be the cause. Diverticulitis should be treated by a doctor.
Everyone is. Different. The most common symptoms of an infection from acute diverticulitis is left lower abdominal pain that can be severe, inability to eat, significant constipation & sometimes loose diarrhea. Can have fever, nausea, vomiting. Rectal pain is not diverticulitis & may be hemorrhoid or fissure. Best to see a doctor.