Ignoring the spiritual part, emotional state does have a well-known feedback loop with physical state. There’s a (largely incorrect) idea in pop psychology that just as happiness leads to smiling, smiling leads to happiness. It’s not nearly that simple, but there are some more straightforward examples: lots of tense emotional states (anger, anxiety) lead to tense muscles (jaw being the classic example). Relaxing your jaw can lead to a (temporary) relaxation of your emotional tenseness. I’ve never heard of a similar result for the lower back, but it’s not hard to imagine. If nothing else, they must be correlated through sedentary lifestyle.