Have you tried hydro type therapies (water therapy .. basically movement oriented while in the water, either swimming or other excercises)? That is less strenuous on the joints and may allow for more healing or strengthening if needed b4 walking. Stationery bikes or ellipticals also - but those can be more strenuous than walking but allow to control the amount of time you choose to be excercising better .. so I am not sure how strenuous you can take .. ?

I didn't know you had been off meds that long, sorry. Sometimes there are other meds that altho are not meant strictly for pain, can help - especially if they think it could be neuro related. Have they tried any neurological medications for you?

Have you ever tried doing sciatic stretches? Even if it is not your sciatic nerve - it may help release pressure ...

Also there are back "stretches" you can try ... simple things like keeping your feet flat on the foor, turn your head upward and reach for the sky as far and with as much strength as you can without taking your feet off the floor - toe touches, stand with feet shoulder length apart and touch the floor flat palms, slowly walk your hands behind you as far as you can without falling .. stop for 3 seconds between each "step", stand upright with feet flat, turn head to the side and reach to that side as far as you can without taking your feet off the floor - then stand upright - then do other side, stand on tip toes n back down then up on tip toes again (as high as you can without losing balance n hold for count of 5). You can also get on all fours and arch your back as far as you can and then return to relaxed position and then stretch out your arms as far as you can keeping head tucked n knees on ground - like a cat would do if it were stretching

These are simple ways of stretching and strengthening the back .. it may help