[Jstuckey]

I had three levels done. The negative level was not the same (more pressure than pain?) and they are very clear in how to answer. They also watch your facial expressions, test you when there shouldn't be pain, etc. Just answer honestly. How uncomfortable it is depends on the person and the situation in your spine. I didn't think it was worse than childbirth, and it's a very short time frame comparitively. (Sorry - natural childbirth will forever be my judge of pain. Don't know if you've experienced this!)
You've probably already had enough severe pain in your spine at times that it won't overwhelm you. I actually had some pretty severe pain at home that night after the discogram, but they should send you home with pain meds. It was gone the next day and I went to work. The CT scan they did after the discogram (while there was still dye in my discs) was very descriptive and helpful for treatment recommendations.
Word of warning.... at least in my situation... the discogram was $9000 which was shocking for an outpatient diagnostic test. I have good insurance that paid 90% - I still had a $900 unexpected bill to pay. You might want a head's up on the cost.