Severe pain in vulvar region only during menstruation

Hi,
I am 36 year old, and mother of two children aged 12 and 6 years. For the past 1.5 years I am having severe pain in the vulvar region ONLY during my periods. Pain is quite severe during urination. I also feel like urinating frequently. Pain intensifies during the 2nd to the 4th day, and then comes down. My doctor initially treated me for possible infection (after ordering tests like R/E of urine and CRP) by giving T. Norflox for a week followed by drugs for 3 weeks. In the next period, pain was a bit reduced (only during urination). But during the further periods, pain came back fully. An ultrasound scan did during that period showed "left adnexal anechoic cystic lesion" of about 5 cm in size. My doctor is now suggesting a laparoscopic procedure to remove the cystic lesion. I am a bit concerned with the surgery. Kindly advise if this pain could be caused by the cystic lesion. Thank you.