If you are having pain during first 14 hours of the menses, you seem to have spasmodic dysmenorrhoea. There are number of causes which can cause this. I shall not go into the details of it.
The pain during menstruation
is only if the egg is released. The birth control pills stop the egg release and hence there is no pain. So you may start birth control pills with the advice of your Gynaecologist only.
Please get yourself examined internally by a Gynaecologist. If the mouth of your uterus
is very tight, it may be the reason for dysmenorrhoea. It may then need dilatation.
Instead of taking only painkiller medicines, if you add some anti-spasmodic medicine to it, it might help you. Meftal spas
is one of such combinations.
I hope this should help you with few options.
Dr. Nishikant Shrotri