As bsml stated, acid reflux sounds like a good guess.
Eating while sitting two hours before lying down (no floor eating) and sleeping with an angled cushion sometimes solves the problem.
You should talk to your dr. It sounds like possibly acid reflux, and yes you can have acid reflux with not symptoms at all. That is called laryngeal-pharyngeal reflux (LPR). With LPR there can be no symptoms at all, but it can cause sore throats, sinus infections, asthma like symptoms, laryngitis... My husband wakes up choking on fluid ocassionally and I have once.
I hope that helps.