Sound like an ulcer or acid reflux?

[Steph152]

My 26 month old son has always been a frequent night waker. We nightweaned (mostly-no nursing from 11 pm - 5:30ish am) at 18 months when I became pregnant with #2, and that helped some. I've always assumed it's just his temperment; some people are just light sleepers. Lately, though, I'm wondering if we've been overlooking a health problem all this time. He just finished antibiotics for the second time in his life. Both times he's had antibiotics (once at 7 months for MRSA and once at 25 months for an unknown bacterial infection), his sleep improved DRASTICALLY. Both times he started sleeping for 6 hours or more without waking every night for almost 2 weeks starting at about day 4 of antibiotics then went back to normal. Normal for him is waking up and asking for something (drink, hug, nurse) 4-6 times between 10 pm and 5 am. We don't see a change when he's recovering or recently over an illness without antibiotics. I've also noticed that he sleeps much better on his stomach or side, but for whatever reason he almost always chooses to sleep on his back. This isn't a subtle difference either; he sleeps for 4 hours at a time on his stomach. After the second time this happened with the antibiotics I'm wondering if he could have a stomach ulcer that starts to heal with antibiotics and then gets worse again after only a short course, especially when I also consider that better sleep on his stomach and his lifelong need for frequent drinks or nursing 24 hrs a day might be indicative of acid reflux. Has anyone had a similar issue? Does anyone have thoughts on whether this might be the case for him or know of any good natural remedies? I read that cider vinegar is great for curing acid reflux problems, but there's no way my 2 year old will go for that, and the same was true for a few others I came across. He eats a good diet, very low in red meat, no carbonated beverages, etc. He takes probiotics every day. Perhaps he has a food allergy that irritates his stomach a lot? Sorry this is turning into a big, rambling thing. I'm just afraid I've been too laid back about what others would consider pretty serious sleep issues when there might be a medical cause that could have been treated a long time ago.