I've never heard of an HSG causing scar tissue. I don't see how it could. They just stick a catheter through your cervix and insert dye. I've heard it clearing out small amounts of scar tissue or fluid actually and helping people get pregnant. Though I don't think that's scientifically proven. Now to prepare you, I had a horrible HSG done. The first one didn't work actually and I had to go back and try again with meds to help soften the cervix. It was mostly due to my cervix I believe. But even with one tube you are going to experience some pain because the dye hits where it's closed. I had extreme pain and then passed out, but it was probably due to them dilating my cervix and forcing the catheter through. That's not common at all, but I wasn't prepared for the extent of the pain and wished I would have asked for higher concentration pain meds instead of just the ibuprofen they recommend before the procedure. Most people just have a small amount of pain. But people with at least one blocked tube will have it worse.