If you can't sit for long without back pain, please see a neurosurgeon, who could most likely decompress a spinal nerve root for you to relieve low back/sciatic pain. It could be life changing.
What do you sit on?
As my system has improved I am spending more time listening but my "sweet spot" is not as comfortable as I would like. I'm looking at new chairs, recliners, etc. This is one topic I have not seen discussed on Audiogon. What kind of chair, perhaps what specific manufacturers are favored by experienced audiophiles? Maybe a little crowd sourcing in this area might turn up some overlooked gems in the way of listening room furniture.