Hello, You are experiencing pain in the right side of the neck. At times, it becomes very severe. It is commonly due to muscle strain / stress, poor sleeping posture or bad posture. Always maintain correct posture when you sit, stand or sleep. Medical conditions that can cause such symptoms are brachial plexus injury due to injury to the nerves connecting to the spine, shoulders, neck and thus causing pain or it can also be due to whiplash. You are suggested to get clinically examined by a GP to assess the possibility of whiplash or pinched nerves, inflammation of the nerves or joints, etc. Get blood tests and imaging tests (X-ray, CT, MRI, etc.), myelography, electrodiagnostic studies done to detect any cervical fracture, cervical disc degeneration, arthritis, etc. Your treatment will depend on the pathology detected that is causing you symptoms. In the meantime, for relieve you can apply heat to the neck or take a warm bath. Try to move your neck gently from side to side. Get connected to a physical therapist for stretching your muscles gently and to do other exercises. Apply pain relieving sprays on the area affected, gentle massage and taking NSAIDS, one stat when needed after food will be helpful. Get examined by a GP, you may need muscle relaxants, corticosteroids or surgery(if required). Stay away from addictions if any. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Nupur K., General & Family Physician