Hello dear I understand your concern Burning during pee and vaginal discomfort suggests lower urinary tract infection due to improper hygiene after sex. Plan B pill cause dilation of smooth muscle of urinary tract also increase the chance of the infections. I would suggest to under go the urine microscopic and culture to confirm the urinary tract infection. Vaginal swab test to rule out vaginal infections. Consult the gynecologist and doctor will give following advises: Tablet septran Ds, Tablet nitrzolium, Tablet pyridium, Syrup cital Wash vagina with warm salted water and then apply apple cidar vinegar. Apply vagisil cream and maintain proper pelvic hygiene. Wear pure cotton loose undergarment Drink plenty of water and fresh juice of cranbery, orange and pineapple. Take healthy diet with antioxidant and vitamin supplements to increase the immunity Hope this may help you Contact HCM for further health query Best regards Dr. Sagar