It seems that the spine is the center of the body and if you have it all the way down the spine then it affects everything else that comes off it through the nerves that get pinched and trapped in the discs of your back. That's my understanding of it but I'm still learning after having it for more than 30 years.

Yes if it is polyarthropathy

Back pain can have an effect on the rest. When mine starts pinching, it hurts to move anything, even my hands. But if you're low back hurts, you may walk differently, which interferes with the hips and the legs etc, that also had an effect on your shoulders. When I started a chiropractor years ago, my one shoulder was lower then they other, due to the way I walked because of the back pain. If I do something to aggravate my low back, that's a little different. But it messes with upper back and neck for me. Hope this helps. Soft hugs!!
Darla-VA

Deep,i think it answers this up on q@a .They still in infancy really trying to understand pain

Hi Deep,
I’m not sure that I could answer that. My lower back causes me a lot of pain, Middle and neck not as bad. It depends on what I do on a day to day basis.
The other issues I have affect my whole body,
Sjogrens is a connective tissue disease, affects the whole body.
Wegners is a rare form of Vasculitis that affects the small and medium blood vessels throughout the body. So combined with the RA, Ostio, and what ever form of Spondylitis I may have, it’s hard to tell what’s causing what sometimes !!