I had an HSG in March. I also had a uterine venogram done at the same time, so part of my experience might have been r/t that part.
I took ibuprofen beforehand. I wish my doc had offered me something stronger bc OUCH. To not mince words, mine HURT.
I have a retroverted uterus, and my cervix sits kind of retrovert as well, and my doc had a really hard time securing the cervical clamps and threading the cath in (he does hundreds of these a year, so I'm pretty sure it was me and not him

).
I had a partial blockage in my right tube and it hurt something awful when he was trying to clear it. It was a burning type of pain. I was in tears.
All in all, it was over pretty fast, tho. I had pretty bad cramping for a day, then was okay. I spotted for a few days.
In reading lots of experiences, I think I'm an outlier, but I do wish I had heard from someone who's HSG was less than no-big-deal first, bc I felt like SUCH a wimp at the time.