Tips for falling asleep after top surgery

So I just got surgery yesterday morning and I know the advice (sleep on your back propped up on pillows blah blah blah). but as a chronic side sleeper i got NO sleep last night. I’m also one of those people who has trouble sleeping if i don’t do at least some rigourous exercise. which obviously I can’t.

Does anyone have any tips for falling asleep in this very unnatural and inactive position?