Talk to Gynecologist on Severe Pain In Anal/Rectum Area

its 2nd time that suddenly pain started in my anal/rectum area which got too much severe (evening time)... pain lasts 30 minutes approx. firstly that pain started in night when I was sleeping and pain last about 20-30 minutes 45 days ago..

*Age 30, weight 69kg, married and have 04 children with C-section.. * both times periods cycle was not started.. * I've constipation issue that I pass stool after 3,4 days... (stool passed 6-8 hours before pain started in both occasions)... * No anal sex ever done... * No piles.... no bleeding etc..

***Can someone elaborate this kind of situation and suggested me the doctor/labs/scans etc