I had my hsg last week, and I haven't had a vaginal birth, just 1 cs. I was told to take 800mg of ibuprofen, and to take 800mg of tylenol that afternoon. I was also very worried about it, because I tend to have anxiety about any kind of vaginal exam/procedure. I just kept trying to focus on what it would look like on the screen, and how it might open everything up instead of thinking about how much it might hurt. My experience wasn't horrible, but then again, I was expecting it to be really bad. My best friend didn't think much about the procedure ahead of time, thought it would be no big deal, and it side-lined her. The cramps were bad enough afterwards that I was glad I had dh to drive me home. I can't imagine how bad they'd have been if I hadn't taken all the ibuprofen! They were very very intense. I've been achey/crampy since it happened, but I've been experiencing abdominal distention/discomfort constantly for months now, so it's not much different. I asked for different doctor than the one who'd recommended the procedure, and although I was very nervous about it since I'd never met him, he was wonderful. The nurse was an angel who was very tender and caring, too.
I hope yours turns out to be "not as bad" for you too!