To divedoc94, i had very similar symptoms to you, could sit, stand, lie down with no pain; only problem was walking, hiking, legs would totally weaken, almost give out.
My MRI showed severe stenosis in two areas, L3,4and5; actually impinging spinal cord plus other issues. I finally saw a spine surgeon and eventually got laminectomies and fusions.
Hopefully, your spine is not that bad and can be handled with PT.
You could also see a spine surgeon for an opinion.