Suggest Remedy For Chronic Dry Cough And Shortness Of Breath

I have had a dry hacking cough for 6 months now along with shortness of breath and tightness in my chest. Last November I had a CT scan and it came back normal. Symptoms persist and last month I was told I had bronchitis and put on antibiotics. Also, I have since started waking up numerous times at night feeling like I can t breath. My husband says I snore loudly. Went to doctor last week, he did a spirometry and it was normal. He gave me an inhaler and hydrocodone based cough syrup but neither is working. Where do I go next?