The thyroid gland is a small butterfly-shaped gland in the neck, just in front of the windpipe (trachea). One of its main functions is to produce hormones that help regulate the body's metabolism (the process that turns food into energy). These hormones are called triiodothyronine (T3) and thyroxine (T4). Many of the body's functions slow down when the thyroid doesn't produce enough of these hormones.
Esophageal spasm is a disorder of the rhythmic waves of muscular contractions (peristalsis) of the esophagus. The cause of this disorder is not known. Symptoms include chest pain and difficulty swallowing.
Esophageal spasm is not common. Often, symptoms that may suggest esophageal spasm are the result of another condition such as gastroesophageal reflux disease or achalasia. Achalasia is a problem with the nervous system in which the muscles of the esophagus and the lower esophageal sphincter (LES) don't work properly.