I (and the doctors) thought I had bronchitis once that was followed by a chronic cough. Then they thought it was maybe asthma. Then I started hacking up stuff while I slept and it was definitely GERD.

But it turned out all of the above was being caused by sleep apnea, and once I got on CPAP it was all cured overnight.

I'm not too familiar with COPD though. But it sounds like some of the symptoms were similar to what I had.