Thank you for consulting Doctorspring. I understand that you had an Upper Respiratory tract infection (URI) commonly called flu, involving your throat first which then turned into a cold with a runny nose and later developed cough.
Due to the common origin of the ear, nose and throat during development, during adulthood too, these are connected in various ways and hence infection in one part can easily spread to the other. Also the mucous lining of the ear, nose and throat are continuous so, inflammations of any part can spread easily to the other. The viruses and bacteria affecting these areas are also similar. So when you develop a sore throat, the most common cause of which is a virus, it can spread to the nose via the oropharynx. Similarly, it can also spread to the ear through the auditory tube. Rarely if severe enough or if left untreated for a sufficiently long time, ear infections can spread to the brain.
But not every sore throat spreads to the brain. This is because some viruses are more capable of causing damage than others or your body’s immune system is not strong enough to fight the virus. There are said to be more than 100 different viruses capable of causing common cold and sore throats. This is why we keep getting a cold once in a while depending on which virus is in circulating in the environment at that time. So, in order to prevent getting colds often it is important to boost your general immunity by eating healthy, staying fit. Foods that are rich in anti- oxidants like Vitamins A, C, E and Selenium are all immunity boosters. If you work in an air conditioned office, try to go to a place with a few plants and get some fresh air every 2 hours.
Usually a bad cold spreads to the sinuses, upper, mid, lower pharynx and to the throat. So when there is a continuous stream of phlegm keeps running into your throat irritating it and thus making you cough. This is usually worse at night. I would suggest that you take a mild anti-histaminic like Cetrizine which will help to reduce the secretions, nose drops can help to clear you nose and throat and reduce cough at night. If cough is really bad you take a codeine based cough syrup. If you are running a high temperature or having difficulty breathing which is not because you nose is blocked, visit your Doctor because you may require an Antibiotic or need a chest X-ray to check for something more serious.