I Started To Get A Dull Pain In Neck Then

I started to get a dull pain in neck then it went to shoulder then to upper back It can alternate between the three.I can lift my arm without any pain.I took Naproxin for 2 weeks and it went totally When I stopped the same symptoms cam back I took them again for 2 weeks and the same thing happened.I am now taking them again but I think they are just masking an underlying problem My Gp is arranging a blood test It started about 2 months ago I am 68 years of age and very fit for my age No weight issues and I eat healthily non smoker very little alcohol What would the blood test be for ?