It does sound like you could either have a urinary tract infection
(UTI) which has itching around the genitals as one of the symptoms. Due to the intense itching you could have irritated the region and resulted in a cyst
The other possibility could be that of a Bartholin's cyst which could be the cause for your symptoms.
Both of these conditions can be treated with antibiotics, which will both relieve your symptoms and prevent future recurrences.
Please also go ahead with a urine analysis, to find/rule out a UTI.
In the meantime, try to wear comfortable undergarments, avoid scratching the region and causing further irritation and drink plenty of water. You need to visit your doctor for proper evaluation, diagnosis, treatment and further guidance towards the way forward.
Hope this helps.