How exactly do you code while laying on the floor? Do you prop your back up at a slight angle with a cushion or something? How is your laptop secured on your lap?
I lay on my stomach (that's what I meant, not on my back) with a hard foam roller + 2 cushions under my chest with the laptop on the floor in front of me (not on my lap).
That is not a perfect set-up, however - my neck and shoulders still hurt occasionally this way. The perfect set-up looks like this: https://imgur.com/a/tmvxHRK or this: https://imgur.com/a/Ej2EY2n - this is how spinal surgery and scoliosis patients study in Russia and Ukraine.
Besides healthy back feeling, effects I experience while working this way include increased energy, decreased appetite and better, more enthusiastic mood (kind of like on ADHD meds - feels like it boosts dopamine or something).
As for laying on your back - it sounds funny but the most comfortable set-up I've ever sat in was a stomatology chair (thank's G-d I have healthy teeth and don't have to be afraid of it :-)) - put a big monitor in place of the lamp, invent a comfortable way to place the keyboard and I'm not leaving it voluntarily :-)
