Thank you for the query.
Every abdominal surgery
leaves some adhesions inside the abdominal cavity. Some adhesion wont cause any problem, however others can impede bowels movements and cause partial bowels obstruction.
Other possibility is that during the C-section some endometrium cells were left outside the uterine in the abdominal cavity. It can be a reason of endometriosis
and give abdominal pains which do aggravate with menses.
You should also have your scar checked to rule out hernia
in this location.
wont visualize partial bowels obstruction. I suggest you to visit gastroenterologist, have abdominal CT with oral contrast (enteroclysis). If this test will also be negative, diagnostic laparoscopy
should be considered.
Hope this will help.