Do lots of people get esophagitis, or is it unusual?

Yes. Esophagitis is a general term for any inflammation, irritation, or swelling of the esophagus. Many things can cause esophagitis, including infections, drugs, allergens or acid reflux. Gastroesophageal reflux disease (gerd) is the most common cause of esophagitis, and studies show that over 40% of american adults experience the symptoms of this disease. http://www.ncbi.nlm.nih.gov/books/nbk6896/.