it can occur in women who have diabetes or thyroid problems. It is also common in women with high levels of a protein called prolactin in their blood...it can be the side effects of certain drugs like oral contraceptives,antipsychotics,antiepileptics...it can be due to poly cystic ovarian disease as well... Menstrual cramps may be caused by identifiable problems, such as endometriosis or uterine fibroids. Treating any underlying cause is key to reducing the pain... So I would suggest you to consult nearest gynecologists for detailed clinical examination and evaluation they will do the needful