John F Dean wrote: I am sure we have a PT/OT person (Jay?) on staff here who can better answer your question for both of us.
It's complicated... and quite a bit out of my expertise area.
The most obvious problem is if the muck shoes have more or less heal rise than your regular shoes. If you're used to a 1" heal, and you suddenly need to wear a 3" heal, there's a good chance your back will notice. But I definitely have heard about "too flat" shoes causing back pain in some people.
Muck boots have a reputation for not having good arch support and they also don't conform to your foot the way a leather tie shoe will. Living on the "wet" coast, my boys wore rubber boots most of the winter. I used to make neoprene insoles for the boots and it was a big help. I used to buy quality insoles for myself, but unfortunately, the "quality" has seriously deteriorated, so now I make my own out of upcycled neoprene wet suits (the thicker ones - thin ones don't last). Even if I'm being fairly active, if my feet get wet, they tend to get cold and then I'm much more likely to get hurt. The neoprene tends to keep my feet warmer as well.
Some boots definitely flex with your foot more than others, so that may be what caused the pain. I have a pair of steel toes for certain activities and I'm aware of having to compensate for the lack of foot movement with my knees and hips. Again, it's possible that John was compensating for problems in hip/knee/ankle joints, and the boots either prevented his usual compensation, or required him to compensate more, and that might have been the source of the pain.
Bottom line is - yes - absolutely - if you're getting back pain, the old song about your backbone connecting to your hip bone, your hip bone connecting with your leg bone, etc is completely true. If someone starts getting some sort of pain, looking for "what changed" and choosing some possible contributing factors and changing them one at a time, makes a lot of sense. Pain in the back is often the result of problems in the extremities, so it's really important to look at the big picture.
Hopefully someone with more expertise will speak up.