Hi, there are various possibilities for such type of pain
As it is associated it is associated with irregular menses & not related to periods you should exclude PCOD
,(By sonography &consulting Gynac)
if this turns to be normal , your urine
check up (routone µscopic )should be done for any problem .Cystitis
or ureteric stones can give rise to such pain.
If nothing is wrong, simple digestive problems with gases may be the culprit.
you have not mentioned about yr. age, any urinary, digestive complaints or white discharge?so no specific advice could be gigen