I have boil like sores on both of labia majora lips which are initially painless but painful later on. Tel possible cause n treatment?

Possible Herpes. You need to see your primary care physician or gynecologist while the outbreak is active. There are definitely other possibilities, but herpes is a prime differential diagnosis. Especially, if you have multiple sexual partners, or in a relationship with someone who has other sexual partners. Be careful, do not have sex until you have a diagnosis, if herpes, it is readily transmissible to others.