If aerophagia goes untreated, what are the complications?

So I think this is aerophagia.

I am new to CPAP as of July 2, 2013. After the first week, I stopped using the ramp as it was totally annoying. Easy enough to adapt quickly as I exhale before the machine kicks on.

My problem is aerophagia. As I'm drifting off, with tongue tucked against palate, I will begin to feel pressure building below the sternum.

History:
I've known I suffer sleep apnea since at least the late 1970s. My ex woke me one night with a precardial thump (a preliminary thump on the sternum previously practiced by EMS and trauma medical staff in the 70s and 80s) after I failed to breathe for over two minutes. He didn't even check to see if I had a heartbeat. He was terrified that I had passed away in my sleep - when I was 18! The idiot didn't even try to shake me awake.
Even skinny as a rail, I was never able to fall asleep on my back. I end up feeling like I'm suffocating and nauseous, which wakes me up, and have to roll onto my side to keep from puking. Fast forward to 1986: I had oral surgery to correct an overbite. Five mm of upper jaw were removed and palate was re-shaped. So when I sleep, even when I am breathing through my nose, my mouth will go lax and gap open five mm! My father-in-law is the one who told me and my current husband that it freaked him out. Knowing this, I still tried the nose and cannula versions of the mask before realizing I had no choice but to use the full-face mask. Now, because my mouth gaps NO MATTER WHAT, I use a chin strap even with a full-face mask to TRY and keep my mouth closed. Not very successful. But, for the first time in my life, I do actually drift off while laying on my back. Kinda nice. BUT now as I drift off to the rhythmic whine of the machine (it sounds very loud to me even though my family says it's inaudible, high note on inhale, low note on exhale, mid note when neither inhaling nor exhaling) I end up feeling pressure building under my sternum. I AM NOT SWALLOWING AIR! This is happening even as I am inhaling, or quiescent! I can't burp unless I put pressure on my stomach. This happens least when I shift onto my stomach. When I do fall asleep, the next morning I experience a loud, long burp first thing followed by passing gas through my intestines until late afternoon. I know for a fact that it's not dietary. I am virtually carb-free on a ketogenic way of eating. I have been diagnosed with GERD in the past but have suffered none of the classic heartburn since April when I returned to KD (ketogenic diet). I'm certain the esophageal sphincter isn't keeping the air out of my stomach. Even tucking my chin or flexing my neck back does not help to eliminate this ingestion of air.
Understand that I don't really experience discomfort. It's just really, REALLY annoying. There's no smell thankfully. Just... lots of noisy expelling. I usually am abdominally bloated but it's hard to tell whether it's the aerophagia or simply my normal girth. I have class III obesity. I am working on losing weight but it is slow going.

Now, if aerophagia goes untreated, what are the potential complications?

Hi - it sounds like you might have a hiatal hernia - and should get your doctor to check it out. Not everything is Cpap related, and even if something is, it may be incidental and need treatment that Cpap (or any of us) cannot diagnose or treat. Get it looked at.

The complication I've noticed thus far has been LPR, since belching while horizontal often brings along stomach acid.

I've been trying sleeping on a long (34") wedge, and that seems to be helping with the reflux, though not at all with the aerophagia.

Have you tried Gas X before bed?