What Is The Warmth And Redness Inside The Vagina?

I experience a warm feeling in my vagina. Not right inside but just inside. On inspection it looks red and inflamed. There is no unusual discharge. Sometimes a bit itchy but more so on the outside. I don't think the itching is anything unusual though. I am married (aged 37) and am not using any contraception. What could this 'heat' sensation be? It's not all the time, it comes and goes, often after sexual intercourse though, sometimes several hours after