On the first day of your period, you will experience a painful swelling in your abdomen, which is a sign of dysmenorrhea. It is mainly because the secretion of prostaglandins increases after the endometrial lining is peeled off during menstruation. Or, the uterus is posteriorly positioned, which causes the menstrual blood to be discharged poorly and causes the manifestation of dysmenorrhea. There will also be soreness in the lower back because there is significant pelvic congestion and uterine bleeding during menstruation. Usually, the pain will be relieved naturally after the menstruation clears. Therefore, it is not necessary to carry out special treatment for the swelling and pain in the small abdomen on the first day of menstruation, as well as the manifestation of lumbar pain, which are normal.