The bones that you sit on (not very eloquent I know) absolutely kill at the worst (generally in the evening when I move around or sit still!) or feel very 'achy' and 'over worked' at best. No pain at the front at all. At times I can't sit 'straight' on my coccyx.
I'm 29 weeks pregnant. Funny thing is that I had this from 7-16 weeks and then it disappeared until 28 weeks :-(