Pain and Soreness??!!!?

I am 18 years old and for the past 2 days I have had pain in my left ! When I woke up this morning my were very sore, particularly my left one. There is a possibility that I could be pregnant, but a very small one. I am on birth control and he also used protection. I just had my period the past week, but it was light and spotty. I am just wondering what could cause this pain in my . Its under my left and its a sudden sharp pain that lasts about 5 seconds, and theres a slight burning feeling. Its only been going on for two days and it hasnt happened at all today but they are just very sore!