It feels good to crack your knuckles. Same with your back (I can do it to myself while sitting in a typical office chair).
Doesn’t mean its good for you. Or its science.
I’ve suffered from back pain, whats helped me the most is an improved diet, exercise and being more posture-focused.
On the diet front, I eat vegan mostly and avoid sugar. I take multivitamins and supplements, particularly ones that improve circulation.
Exercise is critical, particularly that which improves your ‘core’. Pulls basically. Tense your glutes to protect your back.
Finally, I watch my posture when sitting for long periods at the computer as well as walking, standing. I try to keep my back up and straight, with shoulders back as much as possible.
