Please let us know whether you had any pre-existing problems before bronchostomy. Doctors have done a good job by doing a bronchostomy and saving your life. It must been an emergency. Doctors have advised medicines to stabilize your condition.
Now, once you are stabilized, the mission is to find what went wrong and plan for further management. A mere 10% reduction in airway size doesn't really matter. But, you seem to have lot of bronchial secretions which needs to be cleared. That's why doctors have advised you bronchoscopy
Be positive and don't lose hope.