At an educated guess, I went to lift a heavy table top but standing side on rather than facing it. I loaded the facet joints rather than the discs of my spine. As such I smooshed a facet joint around my T9 vertebrae which triggered a cascade of nerve problems and muscle spasm through my right side thoracic spine. I've woken up in 80% less pain today. My protocol of two valium (10mg diazepam), some magnesium pills, a foam roller and a massage ball seem to have taken the brunt out of it. I'm still sore but I can move around without lots of pain.
Totally agree. I've lost count of how many times I've told someone I can't do XYZ and they have said "no it'll be fine". Yes I might be able to do it, but I'll pay with pain for hours or even days.