I rescued a yearling boa constrictor once - the keeper let it get rather cold over Winter. When I received the snake, it would inflate its neck somewhat like you describe.

I took it to a vet, and a few doses of Baytril later (and a proper cage) the snake was just fine.

When you moved, did the humidity or temps change radically? Temp/humidity changes plus new stress can enable an infection. If that is what this problem is.
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Mark