Suggest Treatment For Cough Caused After Injury To Chest Wall

I was in a car accident about 5-6 weeks ago where the airbags deployed and I suffered chest wall injuries. I was treated at ER. Chest x-ray was normal as was a follow up x-ray a week later. The pain is gone pretty much though I still get a little pressure at times. However, I have an irritating cough and feel minor tightness with breathing that hasn t gone away. I am getting enough oxygen and can breathe deeply, but the shallow breathing is still causing me to cough and be just a little lightheaded. I m still under care of a doctor. He told me it s from the bruising to lungs and chest (but no more serious injuries were found) and that it will take time to heal. I just need to rest. Reading online under chest wall injuries I don t find many people that have this issue well after the accident. I can get relief from the cough and minor breathing irritation when I rest but it returns with any movement. It wears me out. I do have a history of bronchitis and asthma when I get the bronchitis but have never smoked.