For Approx. 3 Weeks Now I Have This Intense Pain

for approx. 3 weeks now I have this intense pain in my right shoulder and neck area also goes down my right arm on frequent occasion. I have complete use and motion of my shoulder and arm. It is most painful at night when trying to sleep. I can't sleep on either side and can only find slight comfort flat on my back. I have been to a MD who prescribed me a muscle relaxer which has done nothing to help. I feel a burning sensation and very painful to the touch when I massage the area. I also had a somewhat emotional breakdown about 3 weeks ago due to stress and was wondering if it could possibly be internal shingles? I have had an outbreak of shingles a few years ago externally on my lower back. do you have any ideas?