I think out loud, so give me a minute here for a serious response. ..
To review, a High Concept is your Character in a nutshell, your Trouble is what complicates your High Concept. A Trouble is not something you can easily solve or get rid of and is fundamental to your character.
*thinking about it* Here's some possible Troubles for you:
Not-So-Friendly Competition - Your shop isn't popular with everybody...
[Insert Name of Shop Here] - If the Shop is a major part of your character's life, there's your Problem.
Perpetually Out of The Office
The Fire Department Won't Come to the Shop Anymore - Maybe not a strong wrong, meant to represent Trouble at the shop.
Everybody's Gotta Eat
Something unrelated to the shop.