Are they related?

Lauren
I'm on the POP pill (Cetravette)  and am about to start 5th month but: 
- my last period lasted 2 weeks long with varying degrees of heaviness
- my latest period is 10 days late 
- last time I had sex it was painful and sore (as if he was hitting something? Although was fairly bare able)
- I have an itchy 'face' and outer lips of my vagina most of the time and I have a scab-like patch along the outer lip which I assume has formed from frictions irritation from scratching 
I know me and my so are clean for sti's and we always use a condom so does anyone know what's happening? Are they all related?
Oh and I've had a neg pregnancy test