What Causes Itchy Sores On Vagina Post Sex?

Good morning Doctor. I have been having this problem for quite a while now. I have been developing bad itchy moments every now and again even had little sores two months ago but they disappeared inside and outside my vigina. Right now what s happening is new, I had sexual inter course on Friday and when I went to the loo to pee on that very Friday I had this tearing feeling happening to me. Now when I pee, well actually when I m about to finish I get this very bad pain, so bad that I actually start crying. I know I ve made mistakes like not using a condom at times but the pain I ve been going through I think I have learnt my lesson. Well last Friday I did use condoms