I am one of the weird people who had the opposite happen ... I was induced with the syntocinon drip, and after 7 hrs (when they'd nearly turned the drip up as high as it was allowed), I was having contractions that could be seen on the monitor, but I could barely feel them, and they were completely painless.

My cervix wasn't dilating at all though, so I'm not sure if that had anything to do with my non-existent pain levels.