2nd pregnancy after Csection; Pains.

Are there any Csection Mummies out there, who can tell me their experiences with having another baby after a caesarean. I am having some pains around my scar, My son is 3 years old as of the first of April, I am having some pains. I imagine it is from my uterus stretching, as in 2 more days I will be 16 weeks. It isnt exactly cramping. I have an appt on the 23rd. I was told if it isnt constant or accompanied with blood & so on its ok. I am just worried because I have a high pain tolerance.. its especially worse, if I feel like I am about to have a BM. thank you for any help or experiences shared!?????????