My discomfort didn't really start until last week. Now it's really all in my back, my butt and my crotch. My back kills me (which is likely from the 3 hour round trip commute to and from work), my butt hurts after sitting for any length of time (on a hard surface or a soft one) and my crotch feels like I'm been kicked.
As for any stretches, I've just started doing what I think is called a dead lift (but don't hold me to it). You can stand or sit. When you stand, you just keep your back as straight as you can and lean toward the floor as far as you can comfortably go. Let it stretch for a few seconds and come back up. I do it a few times. You can also add a light weight, if you feel the need, but I wouldn't go over 5 pounds unless you were regularly working out already. If you do it in a chair, it's basically the same, just try to sit towards the edge, but not too far... you don't want it to tip over.