Vaginal pain after sex is common. This is especially true if there has been a long period of time since your last encounter, and if you have never had kids. This pain usually goes away within a few days and you are less likely to have it again if you have intercourse soon. There is a possibility that you suffered from a minor abrasion inside your vagina which resulted in a small cut. This type of thing can happen for the same reasons as above, but most of the time means that their was inadequate lubrication during intercourse. The use of a small amount of personal lubricant on the condom or inside of you can prevent this. This is what I recommend first if someone comes to me with this problem. If you did not notice any blood coming from your vagina after intercourse, a significant abrasion is unlikely.
I think this is the type of problem that could be dealt with by your primary care doctor
such as a family physician
or internal medicine physician. I suggest that you schedule an appointment today. Depending on the description of your symptoms, your doctor may want to examine you down their to make sure that no major problems have occurred. Good luck.