Suggest Remedy For Constant Pain And Discomfort Near Shoulder And Neck

Hi, I pulled my right should & neck due to over stretching for an object on floor, over 2 years ago. I have had constant pain & discomfort in my right shoulder & neck, on & off. I recently saw my GP & he recommended pain killers, & I had a blood test & x ray, which show there fine. I am still have pain, what could it be? Please help. Sarah