Hey honey
I had a HSG about 8 days ago, I'm the worlds biggest wimp, I have to take DF with me just to get blood taken
I took 2x500mg Paracetamol and 2x500mg of Ibuprofen about 45 mins before I went, generally it was ok, not comfortable but not that bad.
Mostly it was like a smear
The worst pain for me was when he had to re-site the catheter and re-inflate the balloon (it moved the 1st time he tried to remove the speculum) it was a sharp crampy pain that did die off after a minute or so.
TBH as soon as they insert the dye and you can see it on the screen it takes your attention and you kinda forget the pain as you watch the tubes light up!!
I didn't have any really bad cramps afterwards, nothing worse than mild period pains, nothing choc ice-cream couldn't cure!
The dye did keep coming out for about 3h and it did make me bleed a little, but again, nothing to bad and nothing they hadn't warned me about.
Good luck honey, you really will be fine