Here was my daughter's experience with braces...
Day 1: excitement, wasn't painful, was easier than she thought. Went to gym practice. All is well...
Evening 1: the braces start moving the teeth... pressure and aching begins and now it hurts enough to interfere with pretty much everything... give advil or tylenol and try to sleep...
Days 2-6: Still achy as teeth are moving. Keep taking the advil, goes to practice, but is a bit moody because it is achy... isn't at her best, but doesn't miss anything (didn't have a competition)...
After about a week, the aching subsides, and she is normal again. Yay!
Occasionally, the braces will catch on her cheek and cause some abrasion (like biting your cheek), but not often. She has wax to put on her tooth if she needs it (rare).
After adjustments (about every 2-3 months in her case), she has some aches and pressure, but not nearly as much as that first week and she always goes to practice or competes. Advil or tylenol if needed, but usually doesn't.