Good thing is that the doctors aren't immediately chalking it up to RSD. It's well worth all the tests to rule out something else, especially if it's treatable.
I got RSD in both hands after Carpal tunnel release 2 years ago this July. The following January, after my second SGB, I literally went to bed with a slight burning on the soles of my feet and woke up with the pain increased.
I knew instinctively and by the way it felt it was the spread of my RSD but was sent back to neurologist by my PM for further tests.
They also thought arthritis, lyme disease, even tested for rare poisoning but nothing showed up...it's the RSD.
I tried the SCS about a month ago, it didn't work for me so I got a puppy He's the best medicine for distracting me from my pain
Good luck Desi...hope you get some answers soon
Jeanne