I have severe pain in my lower back, which can take me down to my knees unless I can catch hold of something. When I bend forward to pick something up or the reverse all my side and back muscles start to spasm and I cannot relax them. I end up walking about rigidly afraid to bump or jolt myself.

You'll need to ask the pharmacist or GP if you're taking any corticosteroids or heart meds but it really may be worth considering a course of Atrosan^® for the inflammation (it's licensed for back pain) and perhaps some magnesium spray to help relax those spasms.

I'm sure your sleep must be interrupted so Dormeasan^® is another option. The Valerian contained within Dormeasan^® is another muscle relaxant, so could be doubly useful to you.

Regarding exercises, I'd have to refer you to a physio since your pain is so severe. I've used one and it was £30 per session well spent. Perhaps your GP could help find one on the NHS?

Best wishes

Earle