Yes, I get that pain too. I've had 2 c-sections.
I asked my doc. He said it is most likely adhesions...which he explained are the result of bleeding inside your abdominal cavity. Surgeons do their best to keep the bleeding to a minimum with suction and such, but it still happens.
My doc said that long fibers of old blood form and connect to various places on your insides like your intestines, uterus, bladder, etc...
The pain comes when you stretch the fiber or break it. Make sense? It did to me, at least when my doctor explained it.
Ask your doctor to be certain.