Hi Marisa,
I had an HSG a couple years ago when we first began seeing the RE. My first try at the HSG was unsuccessful due to my cervix being so closed. It was done in an outpatient procedure room and the doc attempted to "pry" my cervix open with some caliper looking things. It was quite painful and she had to give up with this attempt. Initially they rescheduled me to come back and have it done under IV sedation but then decided due to me having CF they did not want to sedate me. Ultimately they decided to use local numbing injections and Cytotec, a drug that was inserted vaginally to soften my cervix which i had to insert the night before the procedure.
The second try went pretty smoothly. The Cytotec worked well to soften my cervix and they were able to get it open. After they were able to get through, the procedure was super simple. They injected the dye and showed us on the monitor as the dye moved through the reproductive system. It was pretty interesting. My HSG showed that everything was "open" and working properly. However, the shape of my uterus prompted them to do a second vaginal ultrasound where they confirmed that I had uterine "septum".
The RE advised that I have the septum removed before beginning IUI. If the implanted egg attached to the septum we would have a 90% chance of miscarriage. This was done surgically a couple months after the HSG.
I think had I not had the septum, the next step would have been straight to IUI since I had no other problems. It was/is presumed the only reason for my infertility is thick cervical mucus. Also the doc was shocked at how closed my cervix was and said that could be a factor.
I think my problem with the HSG is an exception and not what you should expect. Like I said, once they were able to get my cervix open the procedure was actually quite simple. I did have quite a bit of cramping and pain but I think that was due to the injections and prying!
Sorry, I feel like I rambled. My story is a LONG one. Believe it or not, that is the really shortened version! LOL. Let me know if you have any other questions!
Good luck and take care!
Edited to add: Prior to the HSG we had completed all the other testing required by our RE. Our RE required us both to be screened for HIV and Hepatitis (and a couple others I can't remember), I had cycle day 3 labs drawn for hormone levels, and my husband was carrier tested for CF.