Why do getting your teeth tightened hurt so much?!?

Yesterday i went to the orthadontist and i got my braces tightened for the first time and they hurt alot! and now their starting to hurt my jaw when i eat! im taking Advil but its not helping that much :( The person put in the wire and then like twisted another wire around one of the brackets. my friend told me that could be the problem. Please help i dont want it to hurt tomarro for my friends birthday party :(