Itchyness and soreness?

Hi, I find that having a few days in a row I am a little sore and have a burning sensation which normally goes away after a day or two and then I am fine. I have had UTI's before and the feeling is completely different. I am a little itchy on the outside of my which is very uncomfortable but goes away pretty quick. My boyfriend and I are a lttle rough together so I'm not sure if I'm just really sensitive down there as I do have really sensitive skin so whether we should include lubricant or something. I am quite sure I don't have any STI's as I always make sure a condom is worn even with my previous boyfriends. Is this something I should be worried about or am I just really sensitive down there? I also read somewhere rubbing against the outside of the can make it a little itchy. Any comments would be most appreciated thank you!