hi I have suffered from flu 4 weeks ago and it has left me with a very chesty cough, i am wheezing most of the time and struggle for breath at times too, it is now giving me on occasions pain in my chest, also i am coughing up alot of phlem, what do you think is the cause. i have been on antibiotics for a week and the doctor checked my lungs last week and saisd they were clear but my cough/wheezing is getting worse.