There is a link between chronic cough and GERD, the pathogenesis is complex and it does not mean that GERD is always the cause of the cough. 

Clinical signs and symptoms include heartburn, regurgitation, sour taste, hoarseness and globus feeling. Despite the fact that some uncontrolled studies have shown that antacid medication improves chronic cough, treatment is still debatable. More recent randomized controlled trials have found no differences between proton pump inhibitors (PPIs) and placebo.^{1, 2}

People with GERD develop chronic cough probably by two mechanisms: Reflex theory and Reflux theory.

1. Reflex theory: The respiratory and digestive tracts share a common embryologic origin, hence a small amount of reflux in the esophagus can trigger an esophageal-bronchial reflex, which causes cough. Rising of stomach acid into the food pipe causes cough.

2. Reflux theory is the most intuitive theory, in which reflux rises beyond the esophagus and upper esophageal sphincter, creating microaspiration when microdroplets land in the larynx or infrequently reach the bronchial tree, triggering cough as a direct defensive mechanism against reflux. This type of reflux is known as laryngopharyngeal reflux (LPR). LPR may lead to the development of a cough as a protective mechanism against the reflux. When stomach acid comes into contact with the vocal cords and throat, it can cause inflammation leading to symptoms such as:

• Coughing
• Hoarseness
• Throat clearing
• Feeling that something is stuck in the throat.

3. Additionally, some researchers are of the view that cough could lead to reflux, which could then lead to a cycle of cough (the cough-reflux-cough cycle).^1,2

Source:

1. What′s the connection between acid reflux and coughing? Medicalnewstoday.  Available from: https://www.medicalnewstoday.com/articles/315888. Accessed May 6, 2022.
2. Sharma S, Hashmi MF, Alhajjaj MS. Cough. [Updated 2022 Feb 16]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK493221/