If you ever have a concern like this , please speak up to the person right then, or even better before they even start working on you.

But I'm very sure no real damage was done , you probably got tensed up and need to do some relaxation and diaphragmatic breathing..
If you have neck/muscle issues, it might have stressed those so a warm shower or heating pad might help too.

Here is a past post with a similar question and advice -
http://neurotalk.psychcentral.com/sh...hlight=haircut