How can I deal with pain in my shoulders, neck and upper back when I walk?

[Donald_S]

I'm 61, overweight, but have lost quite a bit of weight over the last 3 years.  I walk for exercise 10 to 15 miles a week.  But recently (say since the first of the year), I am getting pain in my upper back between my shoulder blades and in my neck, after I've walked maybe a mile or so.  I'm trying to remember to walk with good posture, and stretch my neck and back before walking, but frankly it's not been very helpful.  What puzzles me is why has this started recently, after I've been walking like this for a few years now.

I've thought about going to see a doctor or physical therapist, but I'm not sure who to talk to.  Also I'm afraid I'll get the "lose weight" pat answer that doctors love to dole out.  Gets them off the hook from actually trying to figure out what might be wrong..  This clearly is not related to my weight, since when I was 30 pounds heavier, I had no issues.  Any suggestions are appreciated.