What Causes Lower Abdominal Pain And Swelling In Vagina?

I had a very severe lower abdominal pain 2 nights ago, it was so severy that i started crying out of pain. It is not as painfull now but i can still feel it, it's like there is something swollen in my vagina. I feel like there is abnormal swelling in my vagina, there is swelling on the left side but not on the right side, and i feel pain in that area. On the out side every thing looks normal. I recently stopped using the pill and started using condoms, i have been in a relasionship for 5 years. What can this be?