I have also been suffering for some years now with pain around my kidneys when lying down to sleep at night. I get around 6 hrs sleep (if lucky) each night before pain sets in. I then get up to go loo and stretch back then return to bed and basically position myself upright in bed just to get extra sleep. We have brought 2 quality beds and they didn't help. I have been doctors but not much joy from them. I have brought laytex foam topper for my bed and that didn't help.
It drives my partner crazy with my tossing and turning anytime from 3am ... I think some the medical research needs to start because there's a lot of people suffering every night and not getting the sleep needed to get through the day!!