I had one done over a month ago, I'm in northern Ireland and I just had to call 1st day of my cycle to get booked in for that week. I didn't find it painful at all, no more than a smear, some people do find it intense but if you do experience any pain it will last no longer than 20-30 seconds. It really is fine. They insert a very fine tube and inflate a tiny balloon which distributes the dye and then they xray it. They advised me to take 2 painkillers 1 hour before and I did and honestly never felt a thing xx