I keep getting a runny nose and sore throat frequently. About seven months back I fell sick and had a fever that lasted for 25 days. When I asked the doctor he told me that it was PUO fever at first and in the end he told me that it was viral fever. However all the blood tests and scans were negative and I did not know the reason for the 25 day fever.. So my question is could this be some fort of respiratory infection like tonsillitis that is causing this fever and what are the further tests that I need to do. I have currently done CBC,
LFT, ELISA
HIV, WIDAL, and a few other tests which were all negative but I still fall sick.