The human body isn't perfectly smooth. It's prone to developing various lumps and bumps. Cysts are just one type of growth many people get. These sac-like lumps are filled with fluid, air, or other materials. They're not usually harmful or painful. Some cysts are so small that they can't be seen with the naked eye. Others can grow to the size of an orange. You can find cysts just about anywhere on the body, including the vagina. A vaginal cyst is usually located on or under the lining of the vagina.