What Causes Persistent Headache Along With Sore Throat And Running Nose?
Please go in to be seen now.
Detailed Answer:
Hello and welcome,
Most likely you have an infection that is causing the headache, chills and sweats.
Influenza can cause a headache and fever and chills but it is a respiratory infection which should have manifested by now with symptoms of a bad cold and a cough.
Given that you don't have any respiratory symptoms, and the headache has been a prominent and continuous symptom, I strongly recommend that you go in to a clinic/ER to be seen now. There a doctor can examine you for possibility of an infection (including meningitis) and get lab tests. There are other possibilities too, such as autoimmune problems, reactions to toxins, neurological problems, etc, but the most likely cause is an infection (which can include gastrointestinal viral infections which can manifest as a headache).
So, given the symptoms you are describing, please do go in to be seen in person now.