Haven't been out on the bike for a couple of weeks now and it's amazing how quickly the pain in the small of the back has returned as the muscles become weaker. Having had a cold and spent a lot of time slouched on a badly-shaped sofa won't have helped either.
During normal times the muscle tone in the lumbar area is good enough to protect my back. I guess I could do some exerises or, perish the thought, get the turbo out....
the back problems you describe are so similar to my symptoms when i injured my back i thought id share what i found in recovery.
i hurt my back around 8 years ago and couldnt move for three weeks (a very bad idea, always keep moving through the pain the body responds very well to movement), use hiking sticks around the house to assist with the moving when in acute pain, theyre so helpful when one needs a poo lol.
i dumped my car the seat was awful and so was using the clutch in traffic, i changed my sofa and bed. all the beds designed to help back pain are rubbish and ludicrously expensive, i got a super mattress from ikea for 500 pound and it still functions great, also turn the mattress over every few months to avoid sleeping in a dip. also splash out and buy new pillows and while in acute pain get new pillows every 12 weeks, good sleep is vital when in recovery.
i tried chiropractors who i found to be charlatans, physio's who i found much better but too busy too expensive and i needed constant recovery not a messily 45 mins per week, yoga the most successful, but only basic yoga none of the technical stuff, just using yoga to get oxygen to my muscles which is what people in back pain need more than anything imo. i also read a bit about the alexander technique which redirects the person in pain to move in a pain preventative way.
i also bought some decent hiking boots (anton) and wear them all the time, they make your feet sweat but the ankle support is fantastic when one considers the ankles support the rest of the structure, and if the ankles are in line and supported when moving injuries are avoided.
finally, avoid stretching unless the muscles are warmed up.