Hello, You had a sinus infection, you can take decongestants and antihistamine to reduce the discomfort. No, it is not the sinus problem that is causing the pain that is radiating from the shoulder to the neck. Injury or condition in the shoulder itself can cause pain in the shoulder to radiate to the neck. However, at certain times, shoulder pain is due to a problem in the neck. Medical conditions like Cervical degenerative disc disease causes pain and irritates the nerve root. Cervical herniated disc, Cervical osteoarthritis and Cervical foraminal stenosis also cause such symptoms. You are suggested to get clinically examined by a GP, get required blood works and imaging tests done. You are advised to stay away from activities that aggravate pain. Physical therapy and exercises will relieve symptoms. Icing the shoulder is helpful. Anti-inflammatory medications and cortisone injections help to reduce inflammation in the shoulder but should be taken only after consultation of a GP. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Nupur K., General & Family Physician