Your history is not clear as per why your doctor has planned you for a c-section as non progress of labour in last pregnancy
doesnt mean you wont progress in this pregnancy too. But if your non progress was due to pelvic inadequacy and if your present baby weight is also more compared to your pelvis which is assesed after an internal examination , then you should go for a c-section. The date your doctor has given to you is a tentative date but if you go into labour before that you should report to her as if the indication for your caesarean is an absolute one, then you need to get it done as soon as you are in labour. What you mean by Back to Back position of baby i cant interpret but if you mean to say that the baby's head is up and buttocks down (ie breech) then you need to get a caesarean or if you mean that you baby is lying transverse then also.
As you say you are having pain abdomen and feeling of push, it is very likely that your labour process has started. So you need to visit your doctor. Also you say you are having swollen labia
( or clitoris
) with associated yellowish green discharge which might be an indication of underlying infection. I hope your bp record was normal throughout and your haemoglobin
levels were also normal as these can also lead to swelling.
Since you are already 37weeks , there is no point delaying management and inviting avoidable complications as you are already term. So please consult your gynecologist soon.