My right (only) labia minora is a little swollen, painful, and a little itchy. i have no other symptoms. what could this be and how can i fix it?

As above : Could be irritation , if it does not improve see your PCP for evaluation and treatment.

May be an abscess: If you have a circumscribed area of painful swelling, you may have a Bartholin's gland cyst or abscess. You can try warm compresses for 2 days if you are not having fevers, nausea/vomiting and are not diabetic. Otherwise, you may need to have an incision and drainage by your family doc, gynecologist or in the emergency department if you do not have a regular physician.