Stable Angina: This is the most common cause of intermittent chest pain, typically occurring with exertion or stress and relieved by rest. The pain is usually described as a squeezing or pressure sensation in the chest.

Gastroesophageal Reflux Disease (GERD): Intermittent chest pain can be caused by acid reflux, especially if it occurs after eating or at night. The pain can mimic cardiac issues but is often accompanied by regurgitation or a sour taste.
Musculoskeletal Pain: Chest wall pain or costochondritis can cause sharp, intermittent pain, especially with movement or deep breathing. The pain is usually localized and can be reproduced by pressing on the affected area.
Asthma or Chronic Obstructive Pulmonary Disease (COPD) Exacerbation: Intermittent chest pain can occur in the setting of respiratory conditions, especially if there is associated wheezing, coughing, or shortness of breath.

Acute Coronary Syndrome (ACS): Although less likely than stable angina if the pain is truly intermittent, ACS (including myocardial infarction) is a critical diagnosis that must not be missed. The pain can be similar to stable angina but may occur at rest and is not always relieved by rest or nitroglycerin.
Pulmonary Embolism (PE): Sudden onset of chest pain that worsens with deep breathing (pleuritic chest pain) could indicate a pulmonary embolism, a potentially life-threatening condition.
Aortic Dissection: Severe, tearing chest pain that radiates to the back can be indicative of an aortic dissection, a medical emergency.

Pericarditis: Inflammation of the pericardium can cause sharp, intermittent chest pain that improves with sitting up and leaning forward. It's often accompanied by a pericardial friction rub.
Pneumothorax: Sudden onset of sharp chest pain and shortness of breath can indicate a pneumothorax, especially in tall, thin individuals or those with underlying lung disease.
Esophageal Spasm or Rupture: Rare causes of intermittent chest pain that can mimic cardiac conditions. Esophageal rupture is a medical emergency.