Appendicitis will give central diffuse pain that moves to the right lower abdomen in a few days.
That's not your complain.
If this pain is associated with diarrhea, it could be bowel inflammatory disease.
Personally, I think your pelvic and abdominal pain is caused by adhesions.
Adhesions are scar tissue that form after abdominal and pelvic surgery, and especially after c-section (developing soon or years after surgery).
They manifest as a cramps, nausea, vomiting and problems with bowel movements.
Consult your GYN, since adhesions can interfere with further conceptions.
Best wishes!
Marija