Why Do I Have Progressive Weakness Specially Around The Left Shoulder And Severe Discomfort Around The Neck?

Sir I have progressive weakness specially around the left shoulder. I always used to have dull pain in my left hand . I have severe discomfort around my neck, shoulder along with problems in speaking fluently.i have also problem of chronic gastritis. I have been facing all these problems with last 14 to 15 years.my cpk level is 351 U/L and lactate level is 24.5 ml/dl.what are implications of the above symptoms and the report.where is the problem and what is the solution