I'm sorry. it does feel like our bodies are breaking down with us trapped inside (I have RA disease, hypoparathyroidism, Raynaud's, degenerative disk disease, moderate hearing loss (born with it), kidney problems due to reflux and I have MRKH). believe me...I get it.
The pain in your low back sounds like the sciatic nerve, mine would cause my entire back to spasm, badly. I also got shooting pains down my legs. I'm on a muscle relaxer all the time to prevent those painful things.
talk to your doc about getting cortisone injections into your spine. the fifth time actually helped (doc tried something diff).