Hi Sue
It is scary I know, I went through it last year.
I think the vast majority of women have no problem with this procedure at all, and take OTC painkillers an hour beforehand. However, some women do experience a problem. Were you told that an anaesthetic would be administered? If not they usually suggest a couple of OTC pain meds an hour before.
What I would say is, if you find things too difficult, tell them to stop. They can't continue if you're unable to cope. They will then organise the procedure with a GA. It is usually very quick and just slightly uncomfortable so you'll probably be fine. BUT we are all different, with varying medical histories. If you want them to stop at any point just tell them to do so. I had to have a GA because of cervical scarring.
Good luck, I'm sure all will be fine: it's good to get a thorough MOT on occasions! x