I've had issues with hiatal hernia in the past, but had it under control with proper eating habits, and limiting dairy intake (slightly lactose intolerant). Recently, I have been taking prescription strength niacin for high ldl, and I've noticed a LOT more heartburn. Then recently, I started experiencing severe pain when I take the first couple of swallows of food, at any meal. The pain is in the lower esophagus area, where I imagine the hiatal muscle to be. It feels like a severe spasm, and the food seems to stick there, and sometimes comes back up (but doesn't feel like vomiting, exactly). After a moment, I might start hiccupping, too. Eventually, the pain and spasm sensation subsides, and I can swallow again, and eat in relative comfort. What is happening?