I have heard about a lot of women getting pregnant afterwards, and indeed, I did after my SHG, but be careful and talk to your doctor about it before you TTC that cycle. In a follow up with my doctor, she thinks the SHG is actually what triggered my ectopic, and also, once you have an ectopic, your risk of a repeat is high.
The HSG I went through was really painful – worse than cramps. I think it must depend on what they find when they’re doing it. My tube blew up like a sausage and it fucking HURT (I have a very high pain tolerance, too), on top of the emotional whammy of seeing that natural conception was not in the cards for me.
Sedation isn’t a bad idea, as a hold against the worst case scenario. Of course I hope for the best case for you.
To add a dissenting voice, I had an HSG done about 18 months ago, and I don’t remember it being particularly painful. I think it was a mildly crampy experience; I know it was over faster than I expected it to be. I don’t have blocked tubes or scar tissue, though.