What can cause vaginal swelling if your not sexually active?

Bartholin cyst?: If you have never been active, then i can't blame it on sexually transmitted disease such as herpes etc...Which can stay silent for years and re-emerges to cause problem such as swelling. But if you just have a bulge on one side with no redness/pain, it could be a cyst..Quite common. If it gets infected, can cause pain. To be sure, check with your doc.. Good luck.