I wouldn't say its neccessarily anything bad, if it goes away after a day then I'd say its nothing to worry about. I can't remember this situation happening to me when I had braces, but I do remember then hurting alot at points, I'm nowhere near an expert or knowledgable besides my own experience and what I've seen online, but if the pain isn't too bad and it fades I wouldn't worry.
PS , be careful with brushing your teeth three times, I've heard that overbrushing can be uneccessary (and possibily unhealthy, but you'd have to check online/ask your orthodontist or dentist about that)