Hi, I understand your concern. The painful bump on left side of your labia majora can be due to- - hair root infection in that area - Swelling & inflammation of Bartholin s gland ,situated on either sides of Labia Majora. It s function being to lubricate vagina by it s secretons.The inflammation follows blockage of the Bartholin duct by i debris/ thick mucus plug. So it s possible even in virgins. The mouth being blocked.. secretions go on accumulating in the gland , thus increasing it s size, Possibility of it s infection ( bad genital hygiene/ scratching) . You seem to have such infection causing pain & inflammation. PLease consult a gynecologist for local examination to confirm the diagnosis. Treatment would follow. - It would be oral antibotics/ anti nflamatory drugs/ local fomentation . Mostly it resolves within few days. -Some cases need incision & drainage.. where an abscess is formed Thanks.