according to the symptoms given by you it can be bartholin cyst
will be located near the vaginal opening and the function is to secrete mucus like secretion which will help in lubrication.
When the duct of the gland gets blocked cyst will develop. When it gets infected abscess
Now you have to consult your gynecologist and get examined.
Depending on the size and symptoms of the cyst the treatment could be,
To keep antibiotics culture should be done for which swab can be taken from the opening of the duct.
In severe cases surgical procedure like marsupialization can be done.