I was fishing with our son yesterday evening at a lake and I must have got a draught. I awoke this morning with desperate pain on right shoulder blade and going down my arm. All day brutal. Am I doing harm with hot water bottle? When in bed I sleep and I put duvet around it. No pain BUT when I get up pain very bad. If I put my arm up behind head I get a bit of relief. Help!! Regards Rosemary .