Its just muscular pain. I've had 2 sections, and in the following three pregnancies after my first section, I have always had pain. Even during this pregnancy (2 years after my last c-section) I still have that pain. Yes its really painful and feels like someone is cutting you right across your belly, its such a sharp pain. But, its just the muscles moving and stuff around the scar tissue.

All is good I would assume that if you were rupturing you would be bleeding, so if you're not - all is good!