Hi mommyto1boy, I just had a HSG as they though I had a Fibroid. Everthing went well and I do not have a Fibroid and my Tubes are clear Yeh! Everything look good.
I unfortunatley had a stubborn Uterus and so the process was a bit uncomfortable and harder. But it really is not that bad and looking on the screen your Dr should explain what is going on.
Most unfortunatley, I got an infection from all the playing around and have just come out of Hospital, so my thoughts are if you feel back pain and urinate alot after, do not ingnore it like me and go straight to the Docs.
In saying that I am probably one in 1000 that had this problem, so do not worry. Plus I am unsual in most things
Let me know how you go and good luck