Calm down, calm down. -turns on some soothing music-
Trust me, it isn't that bad. It is hard getting used to the braces during the first week and after the first tighten/"readjustment," but after that it's not that big of a deal, and the pain does go down and eventually go away entirely.
Here's a link to an orthodontist's website and his opinion on popcorn:
And a second:
Most of all, it's important to listen to your orthodontist. If he/she says popcorn is alright, then go for it. However, listen if he/she says it isn't. They ban you from certain foods for a reason 
Here are some links to helpful posts you may/may not have read on here already:
And soon I'll be posting a Life Hacks: Braces about braces flossing... the most difficult (without question) part of having braces.
