Hi,
Welcome to ehealthforum,
The pain that you describe could be due to incomplete rupture of hymen, possibility of repeated vaginal injury, PID, vaginal infections, cervical erosion/dysplasia etc. The exact cause can only be made out after thorough examination and tests like vaginal swab/smear test, PAP smear test, etc. You should consider visiting your doctor/gynecologist soon. If infection is detected, get your partner also treated simultaneously to prevent re-infection. If hymen is found to be the problem, surgical rupture would be attempted to ease your symptoms. Drink plenty of water.
Take care.