I have had been having sex with a lad I know and recently we had unprotected sex a few times in a short period and since, my vagina has been very irritated, sore, feels like its burning and swollen. What is wrong? Could I have caught an STD?

You will need a doctor to diagnose whether this is an STD or infection or ? Make an appointment and don't have unprotected sex if you are worried about STD's.

An STD is possible, but there's no way for us to diagnose you online. You'll have to see a doctor if you want to know what's going on.