Is the cough deep in your chest, vs. an irritated throat? That's what I had for years - bronchitis after every cold. Usually lasted 3-4 weeks, kept me up at night, etc. Miserable way to live. Lozenges and tea/honey won't touch that because it's down in your bronchial tubes and not in your throat.
You can treat the symptoms, as others have suggested, with breathing treatments - but remember that those chemicals are pretty strong and cause side effects in many people. If you are allergic to a lot of meds, you need to be very careful.
You can also treat the CAUSE, which is a compromised immune system. Most of us have that because of our depleted foods and deficient soils, plus pollutants and environmental toxins in the air, in our cleaning products, in our carpets & cushions, etc. Even if we "eat right" we don't really achieve that - the American Medical Association said 10 years ago that everyone must supplement because even fully organic diets can't meet our needs. My family has had extraordinary results with patented nutrition - no bronchitis in 4 years, no colds, no flu. We don't get flu shots anymore and we do not need any of those products you are spending a fortune on (cough meds, zinc, etc.). We aren't meant to get our nutrition in pieces - so buying a single ingredient (echinacea, zinc, vitamin C, whatever) is rarely successful. That's why those aisles and aisles of individual vitamins aren't making us healthier as a society - we are sicker than we have ever been, and so many kids are getting diseases that used to be "adults only" and why we have so many babies with reflux and food allergies. Anyway, that's what I've learned in my years as a nutritional consultant.