What Causes Soreness In Vagina?

It started with a slight soreness in vagina that felt as if I had had too much sex, however I was on my period so I had not. The next day my vagina began to itch and has slightly on and off since. On top of that I have began to get sharp pains in my vagina every now and then, phases of this also come and go. I am on the contraceptive pill and have also had cystitis twice recently. I do not have time to go to the doctor's until next week so was wondering if you could suggest what it might sound like please? Thank you.