Hi deekeun, and thanks for your post. While I'm hopeful others in the community will see your post and respond by sharing their own experiences, I have something to add as well.
Does this happen every time you cough? This sounds like it is one of those unusual 'symptoms' associated with COPD. We actually have a published article, right here on COPD.net, which focuses on several unusual symptoms (but sadly, not the one you described). I thought you might find it interesting to look this over: https://copd.net/living/the-unusual-symptoms.
You may also want to post your concern on our COPD Facebook platform. We have many members who interact there throughout the day (and night), about all things related to COPD. That might increase the audience for your question. You can access our COPD Facebook page through the link on the bottom of this page.
What do you think?
Leon (site moderator COPD.net)