I'm about 33 weeks with my second, and i've been feeling that for about a fortnight already !!!
Your baby's head has dropped into your pelvic cavity, and the presure on the nerves there causes all that pain- it can also spread down the insides of your legs. I didn't feel it so badly with my first, but this time... Yyeeeoowwcch.
Heat can help, although it's a tricky place to balance a hotwater bottle, especially when we aren't supposed to be lying on our backs. I use one of those wheat bags you heat in the mocrowave- a long one, and I put it between my legs, it reaches up my back a little, and up to my pelvic bone at the front.
You can take paracetemol, see if it helps. The bad news is, that once the baby gets into that spot, they don't tend to move out of it again- they like it there.
Just try to find some comfy positions to lie in, be creative with pillows, take it easy and lie down when you can, I didn't think i'd be able to stand another 10 weeks of being pregnant with that amount of discomfort, but now, 3 weeks later, i'm kinda used to it.
Hang in there.