I thought it was your glutes that were sore, not your back. How much did the new one cost?
Backs are often the underlying problem that needs addressing. Not sure I would trust a coffee shop to sell a new back tho.
It may have been a coffee shop and a back shop next to each other. With the upturn in cyclists visiting cafes, it's probably good as a complementary business venture.
I thought you had other solutions for back problems?