Normally, the things we eat and drink stay in the stomach to be digested and do not spill back up into the oesophagus. However, if the valve at the lower end of the oesophagus (the oesophageal sphincter) is weak then heartburn and reflux may occur. This is when acid passes back up into your upper throat (pharynx) and voice box (larynx), causing the tissue become inflamed resulting in a sore throat and perhaps a hoarse voice.

This is typically known as laryngo-pharyngeal reflux (LPR), and can occur during the day or at night, even if you haven’t eaten anything. It is also known as ‘silent reflux’ because many people do not experience any of the classic symptoms of heartburn or indigestion.  

Due to the repeated instances of acid in the oesophagus, some people experience a chronic sore throat.  This may be worse on waking due to having been laying down for a long time.