Pulmonary Embolism (PE): This is a common and serious complication following orthopedic surgeries, especially those involving the lower extremities like tibial fracture repair. The immobilization and surgical trauma increase the risk of deep vein thrombosis (DVT), which can lead to PE. Chest pain in this context, especially if it's sudden, sharp, and worsens with deep breathing, should prompt an immediate investigation for PE.

Fat Embolism Syndrome (FES): Although less common than PE, FES is a significant consideration in patients with long bone fractures, including tibial fractures. It occurs when fat globules are released into the bloodstream and can cause respiratory, neurological, and dermatological symptoms. Chest pain can be part of the presentation, along with hypoxia and petechiae.
Pneumothorax: This could be a complication of the surgery itself, especially if there was any accidental injury to the thoracic cavity during the procedure, or as a result of barotrauma from mechanical ventilation. Chest pain and shortness of breath would be key symptoms.
Myocardial Infarction (MI): The stress of surgery, along with possible pre-existing cardiovascular disease, could precipitate an MI. Chest pain is a hallmark symptom, although it may present atypically in the postoperative period.

Aortic Dissection: Although rare, this is a catastrophic condition that requires immediate diagnosis and treatment. Severe, tearing chest pain that radiates to the back is classic, but any chest pain in the postoperative period warrants consideration of this diagnosis.
Pulmonary Hemorrhage: Bleeding into the lungs could be due to various causes, including anticoagulation therapy, and presents with chest pain, cough, and potentially hemoptysis.
Cardiac Tamponade: This could result from a complication of central line placement or as a result of the surgical procedure itself. Symptoms include chest pain, hypotension, and decreased cardiac output.

Spontaneous Pneumomediastinum: Air leaking into the mediastinum can cause chest pain and could be related to the surgical procedure or barotrauma.
Esophageal Rupture: Iatrogenic from intubation or due to severe vomiting, this condition presents with severe chest pain and requires urgent surgical intervention.
Stress-Induced Cardiomyopathy (Takotsubo Cardiomyopathy): This condition mimics MI but is caused by extreme stress (in this case, possibly the surgery and pain). It presents with chest pain and signs of heart failure.