This is only information not advice. Bronchitis - "itis" means inflammation. Bronchitis, if that is what you have or any other kind of inflammatory problem is an immune response. The body is trying to protect itself from something getting into the sacred body.
There are three ways that invaders get into the body: 1. The skin - that is not likely unless you have a cut or an opening in the skin. 2. Breathing - If you are not working in a toxic environment you probably are not breathing in the invader. 3. The digestive tract - 90% of all triggers are getting into the body through the food we eat.
Your job is to identify what is it that you are eating that is causing the immune response and eliminate that food. This is done by finding what are you eating that causes gas, bloating diarhea, constipation, cramps or any other digestive problem.
Why the doctors did Xrays and CT scans only proves they have no clue what causes Bronchitis. You are paying for a diagnosis but no understanding of causation.