I read Jeff Tweedy’s book on songwriting and he talked about borrowing themes from anything and every thing. Like that chord progression? Use it. Interesting cadence or rhythm? Borrow it. It’s not really copying, but more so taking inspiration from other works. It’s always good to keep your ears open to try to find things in the world that resonate with you. I often sit in my back yard and listen to the birds sing and imagine what a bird song would sound like applied to something on guitar or lyrical cadence.
Try some Yoga. It can be a decent workout and will definitely help with posture, soreness and flexibility if you stick with it. Check out some beginner yoga routines on YouTube to see if it’s something you would be into.