It used to be that when someone had a "bad back", the doctor would prescribe bed rest. We now know more. We know that limited activity is actually much better for your back than doing nothing, if you're interested in a speedy recovery, that is.
Just the same, there are those times when a little R&R is necessary.
For some, the idea of laying around and doing nothing provokes anxiety - it would for me. This is because most of us thrive on accomplishing things and/or having a lot to do all the time. If that's your issue - here's a little (non-medical) "therapy: How to Keep Busy When You're Laid Up With A Bad Back.