I think these are like everything else- the pain is subjective. I had one last year and thought it fairly painful while it was happening (the needle part). But to be honest, in retrospect, I guess it really wasn't that bad at all. Since then, I've encountered two people who had the same exam as I did. One of them recalled it as very painful, the other thought of it in fairly neutral, almost benign, terms. As others have said, it could be a combination of the sensitivities of the patient and the expertise/gentleness of the practictioner. The worst part may be the fear of not knowing what to expect, but try to remember that any pain is really just a temporary blip and doesn't linger.