Suggest Medication For Viral Flu Along With Stiffness In The Neck And Headaches

yes I have 16 year old daughter whos ben diagnoised with viral flu,,placed onibuprofen ,tylenol and codiene for pain....none have stop pain and stiffness in her neck nor have they stop the severe headaches..now also her eyes have crossed or something....seen doctor ttwice, blood work and other test shows nothing wrong please help meeeee......