Thanks for the query.
According to your description there is possibility of some vaginal infection
Emergency pills can cause side effects related to menstrual period. But they may not cause that much severe vaginal pain
So you better consult gynecologist once and get examined to find out the cause for your problem.
If vaginal infection is detected you may need local and systemic antibiotics.
Both partners have to take them to avoid future transmission.
For more details you can ask me through: http://www.healthcaremagic.com/doctors/dr-sree-gouri-sr/63429