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Based on descriptive history, I come to the conclusion that it started off as a viral infection (a sore throat) and has progressed to a secondary bacterial infection which has manifested as a cough with phlegm and due to phlegm accumulation in your sinuses, you are experiencing strange sensations in your head.
I would advise you to go for saline gargles (lukewarm water with a pinch of salt added) and Betadine sore throat gargles alternatively till you get your throat clear. Try swallowing a tablespoon of honey twice a day to soothen your throat. Start a course of Azithromycin antibiotic as it is the best suited for such respiratory infection and you will only have to take three tablets in a total of 500 mg once a day for three days. And start an expectorant cough syrup which has Guaphenisin in the contents, take 10 ml each thrice a day, it will relieve you of the phlegm. Take care.