2. Pain that worsens when you’re lying on your back:
When you stand upright, gravity helps keep the contents of your stomach in your stomach where they belong. But when you lie down, there’s nothing to stop them from flowing back upward into your throat, where they can cause pain and discomfort.
3. Pain or nausea after eating:
People with acid reflux often experience indigestion after a big meal. This can feel like stomach pain or queasiness, and as mentioned it often worsens if you lie down. (Do note that if you find yourself experiencing recurring stomach pain after eating that you should be evaluated by a doctor to rule out other conditions such as ulcers.)