My middle back hurts bad

[DrPhilbigone]

Wooden chair chair I was sitting in collapsed causing me to fall backwards. The wooden part of the chair hit the mid section of my right side. Since October of 2018 I have been to three different doctors,has mri,xrays and cat scan. Every doctor has told me other than degeneration or spinal stenosis they see no problem. If I wear a back brace like from Walmart my pain is tolerable.  As soon as I take brace off severe pain sets in. At night very hard to get a position in bed that does not hurt.Wife tends to think maybe broken rib that no one has identified.  If I lift a case of water it's hard to walk next day or so. Any clues. Please help.