Maybe you should find a "Family doctor" to analyze your problem and order any necessary tests for you., like the pulmonary test. It may be COPD , for Chronic Obstructive Pulmonary Disorder. There are other medicines that can be described besides the inhaler. What may help you, is drinking a few glasses of water per day and see if that helps thin the mucus, which will help reduce your cough.
You need to be looked over by a family physican.
You really need lung function tests to see how your lungs are doing as far as working goes. Those tests will also provide very useful info as far as what the problem may be, there are ways of telling if there is an obstructive defect such as asthma or if there is another problem that needs to be addressed.
There is also the matter of possible allergies that need to be addressed as well. You need a thorough workup in this department as well to determine if allergens are causing your problems. There are many treatments that can decrease even alleviate your symptoms. An allergist is the specialist to turn to as far as identifying possible allergies.
Perhaps they should also look into doing a chest CT to see if there are structural problems in your chest that aren't as easily identifiable in chest xrays.
If all pulmonary tests come back clean, then the tests of the heart should be carried out. Many disorders cause shortness of breath, even wheezing.
You really should find a specialist and quickly if you haven't already. Preferably at an university teaching hospital. A good pulmonologist is invaluable to your health.
Keep pushing, don't be afraid to be persistent. I hope you get answers soon,
Yeah I would definitely have suggested getting a primary care physician and having them look you over . They'd most likely order you a PFT.