Thanks for your question. I recommend that you speak with your doctor
, possibly an ENT, about your concern. Certainly it is possible that viral infections can lead to bacterial infections, and then these bacterial infections can go on to become chronic infections and in some cases this can lead to a case of a chronic lung infection. In someone who is otherwise well as a 17 year old, this may be less likely, however, than many other potential options. Most often, the need to clear the throat frequently is not the most common sign of a chronic lung infection. Instead, this would be a sign of something that is irritating the vocal cords. Post nasal drainage is one common cause for this, and so it was a reasonable idea to treat you for a sinus infection. If you have had no improvement in your symptoms after that, then it may be prudent to consider other causes. In this sort of situation, acid reflux
or laryngopharyngeal reflux is one of the more common causes. Eating late at night, eating lots of caffeine, alcohol, or chocolate, and being overweight can all lead to problems with laryngopharyngeal reflux. Your doctor, possibly an ENT, should be able to help with this and to consider other causes. Please speak with your doctor about this question.