If you have a cold without fever but have a headache, it may be caused by viral stimulation, nasal congestion, viral encephalitis and other reasons. 1. Viral stimulation: Colds are caused by viral infections, and after the virus enters the bloodstream, it can cause inflammatory reactions and produce inflammatory factors such as prostaglandins, which stimulate the local blood vessels in the head and lead to microcirculation disorders in the head, resulting in dizziness, headache and other symptoms. 2. Nasal congestion: Colds usually cause congestion and edema of the nasal mucosa, leading to nasal congestion and other symptoms, which can indirectly cause headaches. 3. Viral encephalitis: If severe headache occurs and there are convulsions and other manifestations, it is necessary to consider the complications of colds, such as viral encephalitis, viral meningitis may be. Headache can also be caused by other diseases, if the headache is not relieved or aggravated, it is recommended to consult a doctor in time to clarify the diagnosis, and follow the doctor’s instructions for medication.