My partner seriously injured his back last year and needed to be hospitalised.
They used heat on his back.
He also got a thermal belt to wear which you can buy from the chemist (I think you call it a drugstore in America).
They definitely recommend moving around - steady walking etc. rather than sitting.
Prolonged sitting is really bad for back pain.
If you suffer from back pain a lot, it's worth visiting a physoitherapist and getting an exercise/stretching plan.
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It's like I'm sleepwalking