Persistent cough

I have been using a Resmed Air Sense 10 for 9 months. The last time I ordered tubing they sent a heated one. No problems. However I got a cold about 3 months ago, then shingles, and a cough has persisted ever since. Doc treated me for bronchitis but cough is still there. Worse in afternoon/evening, not too bad at night. Ive had a chest xray and chest CT and both were normal.
Could this cough be caused by my CPAP therapy??
I empty the reservoir every morning, use distilled water... Ive got the humidity set on 4, never had a problem before but I was using it in dry winter weather. It is hot and humid here now, in the summer.
Any thoughts would be appreciated. Thank you.

hmmmm....I'm getting the coughing too. I never thought it could be the CPAP, but maybe there is something to that. I don't use a heated tube. It is summer where I am, and I thought it was allergies. I didn't have a cold.

Are you changing your filters regularly? How about your hose? Have you changed out your mask since you had that cold? It would be a good idea to do the necessary things to clean up your therapy if you haven't already done so, and then check with your GP concerning your persistent cough. This merits a doctor's follow up. Since 3 months have passed with the cough, it wouldn't hurt to just check in with your doctor first.

Another idea is to remember to hydrate adequately. It takes a lot of fluid to overcome a cough.

I once had a persistent cough (3 months following a cold/flu) and my doc prescribed an inhaler for me even though I don't have asthma. It worked. Good luck to you and take care.