As the other girls said, you need to see your Dr. That could inicate an infection.You said that your vaginal opening is very tight ? It could very well be that you or your husband needs to "stretch" it out a bit. Kind of how they did when you give birth and your trying to crown.. Use some rose mary oil and try stretching the perinium, but be careful. I would see a Dr. first and see what they say.
I think you should visit gyn. asap it could be infection.
It sounds like you may have a thrush. You shouldn't have a pain if you are having intercourse. Pls see a doctor, you may also have a UTI. It's nothing serious, just very painful, and common. See ur dr asap. All the best. xx