Why does hiccups sometimes not stop?

Hiccups aren't actually your stomach 'protesting,' but rather your diaphragm suddenly contracting involuntarily, followed by a quick closure of your vocal cords, which creates the familiar 'hic' sound. Eating too fast, eating too much, drinking soda, alcohol, or suddenly changing the temperature in your stomach can all irritate the nerves controlling your diaphragm, causing it to start contracting irregularly. Usually, they stop on their own within a few minutes to a few hours. Many people hold their breath, drink water, or swallow a large gulp of air when they hiccup. These methods can sometimes temporarily stop hiccups, but no single method is guaranteed to work for everyone. What you really need to pay attention to is when hiccups persist for a very long time, especially if they don't stop after 48 hours and affect your sleep, eating, or breathing. In such cases, it's not just ordinary hiccups, and you might need a doctor to find the underlying cause. So, having a few hiccups occasionally is normal. What's truly strange is 'hiccuping for two days straight without stopping.'