Hello, will suggest first to rule out any injury to shoulder go for primary things like x-ray for any pathology. If it's normal Check for thickness of pillow and mattress is it proper or not and check for material sagging. Correct posture and workstation with the help of ergonomics. Then strengthening of muscles is important. Seek physiotherapist and Ergonomist. Regards

Hi, any muscle spasm, physical injury,bone damage, dislocation can cause continuous pain. If. You are able to move your shoulder normally we can rule out dislocation. Go for xray shoulder of affected arm. You can do massage in case of spasm, give rest to that arm. Consult orthopedician for furthur evaluation and treatment.