It is possible you are not elevating the head of the bed enough. Dr. Huitte at NJH wanted me to sleep at 30-45 degrees because of GERD. Studies have shown that gastric aspiration can happen up to 30 degrees, which happens to me. Therefore, I sleep at >40 degrees. Initially, I was not able to visually gage the angles, so I ordered an inclinometer from Amazon and surprised myself with how wrong I was at my estimates. A 30 degree angle is pretty high. It wasn’t easy to get used to the inclination. It took me 2 years and still not comfortable. My husband, with GERD but not NTM, was unable to sleep inclined. Because the bed is a split king, we have the freedom to select our positions.
If you choose to sleep on your side, make that the left and not the right. There is a lot more aspiration on the right because of the shape of the stomach.