Yes I have this exact same thing when I am not taking the pill and so does my mother. There is apparently a name for it but don't know what it is. I can find out the name for it. I don't think it has anything to do with your c/s as I know there is a medical condition that its called and its exactly what your describing. I get it for the first few days of my period then it starts to ease off and it feels like a sudden onset of a knife going in your butt literally. My afterbirth pains were exactly the same. It is especially bad when you need to go to the loo for what ever reason. Are you on any contreception? Mine if its the same thing as yours is much better if I am on the pill which I am not as I am ttc. You could try some ponstan its an over the counter analgesia that might help.