pain under belly button

hi im 35 wks n 5days preggies with no2. im getting some pain jus under my tummy. it happens after i sit or lie down n when i stand up its really bad. i hav 2 wait a few seconds b4 walking. its ova a week dat its happening now
when i asked doc she says its coz i had a c sec previosly n because im carrying baby very low in pelvis im getting pain.
but it seems 2 b getting more painful as da days r going. should i b worried or is this normal.
and oh sometimes da pain goes lower into da triangle area