It has been six months since I started walking 3x daily.
I am able to walk for an hour without pain now.
There is a feeling of discomfort in my shoulders which starts 10 minutes or so into the walk. I found that wearing an intelliskin shirt takes care of it - I can walk with no pain or discomfort.
The shirt seems to restrict blood flow somewhat so I only put it on when I walk.

I also found that running for 5 min each time I walk improves blood flow and helps relax the neck muscles - makes the symptoms go away for an hour or so.
Too bad I can't run all day