^^ what Data said. Depending on where it hurts, you can also roll a bath towel up and put it behind you for extra support in the middle or lower back area. And you can use a couple of them to brace yourself, or prop yourself up a bit on one side, when you sleep. If that helps.
(Ask me how I know, yeah I got better, I hope you do too and soon.)
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"I believe you find life such a problem because you think there are the good people and the bad people," said the man. "You're wrong, of course. There are, always and only, the bad people, but some of them are on opposite sides."
-- Terry Pratchett, Guards! Guards!