If I have lots of sex and sometimes forced the penis in when I was dry, could that give my vagina a sore spot? It feels like a sore right inside me only on one side. It hurts a lot to have sex, but then about halfway into it, it doesn't hurt as bad.

Yes, it could.

So if I lay off on the sex, this will go away?

You have to be properly lubricated for this not to happen.