You may be injured
Most likely you sustain an injury to your soft tissues.
I think it's a good idea to see your Gyn. The location of injury will determine if you need any special treatment (stitched for sizable laceration) or no treatment at all. Sitz baths with Epsom salt may sooth the irritation in injured area. Additioinally, I'd advise to stay away from inercourse for at least a week.