Hi Dan-O,
I had a HyCoSy at the end of last month. It was fine. It is very similar to a HSG except they use ultrasound to look at your uterus/ovaries instead of x-ray. They had a bit of trouble getting the tube into my cervix, which was uncomfortable rather than painful. I had a few mild cramps when the dye ran through, but it was all very cope-able with.
Nearly forgot, have you been prescribed any painkillers and or antibiotics. I was, but know that it varies from place to place. If not then take an ibuprofen before hand.
Best of luck!