I think you should certainly have another session with your surgeon especially as (from what you say) the pain seems to originate from "within your abdomen" rather than from the surface surgical incision.
regards
Morecambe
the surgery was a resection.
From your posting I am not sure exactly what treatment you received. Diverticulitis is a condition of the colon in which "outpouchings" ("bulges") become infected and cause pain. If antibiotics do not work then sometimes all or part of the colon is removed (= a total or partial colectomy). After surgery, pain is managed epidurally but you should be almost pain free after ~5 days. If you still have pain then do see the surgeon again in case the cause is based on the original surgery. Your surgeon is responsible for your recovery after treatment/surgery.
regards
Morecambe