Hello Looking at your history this could be due to cold induced allergy and subsequent Sinusitis Another possibility is fatigue induced headache or cluster headache Instead of CT scan I would advise you for an X ray PNS or an MRI and MRV of brain You can take ibuprofen for headache Boost your immunity to fight against common illness Have good balanced and nutritious food with multivitamin supplements Have citrus fruits like orange and lemon juices Avoid direct exposure to cold by covering your nose and mouth Have plenty of fluids, keep yourself well hydrated Hope this addresses your query Thanks for your question wish you good health Regards