Musculoskeletal Chest Pain: This is often the most common cause of chest pain in young adults, resulting from strained muscles or inflammation in the chest wall. It can be related to physical activity, posture, or even minor injuries.

Gastroesophageal Reflux Disease (GERD): GERD can cause chest pain that may be mistaken for cardiac issues. It's common in young adults, especially those with poor dietary habits or who consume alcohol and tobacco.
Anxiety or Panic Attacks: These can manifest as chest pain or discomfort, often accompanied by other symptoms like shortness of breath, palpitations, and fear of dying. Young adults, especially those under stress, are prone to anxiety disorders.
Pneumonia or Other Respiratory Infections: Although less common in healthy young adults, respiratory infections can cause chest pain, especially if they lead to pleurisy (inflammation of the lining surrounding the lungs).

Myocardial Infarction (MI) or Heart Attack: Although rare in young adults without risk factors, it's crucial not to miss this diagnosis. Family history, drug use (e.g., cocaine), and certain health conditions can increase the risk.
Pulmonary Embolism (PE): This is a life-threatening condition where a blood clot blocks an artery in the lung. It's essential to consider PE, especially in patients with risk factors like recent travel, immobilization, or family history of clotting disorders.
Aortic Dissection: A tear in the aorta's inner layer can cause severe, tearing chest pain. It's rare but critical to diagnose promptly, especially in individuals with hypertension, aortic valve problems, or certain genetic conditions (e.g., Marfan syndrome).

Pericarditis: Inflammation of the pericardium (the sac surrounding the heart) can cause sharp chest pain that improves with leaning forward. It's more common in men and can be associated with viral infections or autoimmune diseases.
Pneumothorax: Air in the space between the lungs and chest wall can cause sudden, sharp chest pain and shortness of breath. It's rare but can occur in tall, thin individuals or those with lung diseases.
Esophageal Spasm or Rupture: These conditions are less common but can cause severe chest pain. Esophageal spasm is often related to swallowing disorders, while rupture is a medical emergency usually resulting from forceful vomiting.