Hello, and thank you for sharing your question with the community. This must be very uncomfortable for you! I'd love to give you some helpful information on the subject.
The urethra is the tube that leads from the bladder and transports, then discharges urine outside the body. In females, it emerges between the clitoris and vaginal opening just as you described.
All the things that could negatively affect the urethra will also bring with it other symptoms such as burning while urinating, irritation, itching and tenderness. Because you do not have any of these other symptoms that point to urinary issues, I suggest that it is related to your outer labia. These are the or large, fleshy folds of tissue that enclose and protect the other external genital organs. They are located on either side of the vaginal opening.
The labia can become irritated and swollen from lack of sufficient lubrication, or vigorous sex. Since you are not experiencing burning or itching I suggest you use soft soaps to keep the area clean and wear cotton underwear.
Let you know if you have any more questions.