Sherry brought up a good question about it possibly happening after you eat. That could definitely be a sign of reflux. If you are feeling well, that should rule out bronchitis. What about allergies, are you coughing up any phlegm? Do you have any drainage in your throat? Back to the reflux scenario, do you have any trouble going to sleep at night because of this? Have you been to see a doctor abut this yet?
I am not a medical professional, but these are the only things that come to mind from what you have described. I would definitely make plans to see your doctor. Please keep us posted.