It seems to me you are doing alot of work because of the snowfall you are experiencing. (Shoveling, dealing with a wood stove, etc.) Those types of activities don't control and isolate movements as much your average exercise routine. I'm guessing that MAY play a role in your neck / shoulder / upper back pain. Shoveling snow can give all of those muscles a really good workout, and you may have pushed a bit too much.