Read this article:
http://www.nlm.nih.gov/medlineplus/e...cle/003779.htm
Look at this picture:
http://i.dailymail.co.uk/i/pix/2012/...70_634x346.jpg
Now you'll know what to expect.
Honestly, as no two human beings share the same experience when it comes to perceptions of pain, no two women share the same sensation "down there". What one finds dreadful and incapacitating another will find sort of uncomfortable. IMO the worst part of most pelvic exams in general is the whole fact of having your naked business hanging at the edge of a table, spread out in a brightly lit room followed by the speculum being inserted. And I wouldn't call it pain, I'd say it's uncomfortable. A very, very large amount of the discomfort is purely psychological, especially if you've never had a pelvic before. The more frightened you are, the more tense your muscles will be, that will make everything harder for everyone involved. Try to think happy thoughts and focus on breathing.
Additionally, when it comes to many medical procedures a LOT has to do with how the technician is handling the job. They are only human, remember that. If you let them know upfront you're nervous they will be very patient with you.