Viral Upper Respiratory Tract Infection (URTI): This is the most common cause of dry cough, fatigue, and chest heaviness, especially given the short duration of symptoms. Viral URTIs are highly prevalent and can cause these symptoms due to inflammation and congestion in the respiratory tract.

Acute Bronchitis: Often presents with a dry cough and can be accompanied by fatigue and a feeling of chest heaviness. It's usually caused by a viral infection but can sometimes be bacterial.
Allergic Rhinitis: Can cause a dry cough, fatigue due to poor sleep, and chest heaviness if there's associated sinusitis or asthma. Seasonal or environmental allergens are common triggers.
Asthma: Especially if the symptoms are exacerbated by exercise, cold air, or allergens. Asthma can cause a dry cough, chest tightness or heaviness, and fatigue due to nocturnal symptoms or decreased lung function.

Pulmonary Embolism (PE): Although less likely, PE is a critical diagnosis that must be considered, especially if there's a history of recent travel, immobilization, cancer, or familial coagulopathy. It can present with sudden onset of chest heaviness and dry cough.
Myocardial Infarction (MI): Can present atypically, especially in women, with symptoms such as a dry cough and chest heaviness, rather than the classic chest pain. Fatigue is also a common symptom.
Pneumonia: Bacterial pneumonia can present with these symptoms, especially in older adults or those with compromised immune systems. It's crucial to consider this diagnosis due to the potential for severe outcomes if not treated promptly.

Sarcoidosis: A systemic disease that can affect the lungs, causing symptoms like dry cough and chest heaviness. It's less common but should be considered in patients with persistent or worsening symptoms.
Interstitial Lung Disease (ILD): A broad category of diseases that affect the lung tissue, leading to symptoms such as dry cough and chest heaviness. ILDs are rare and often require specific diagnostic tests for identification.
Lymphoma: Although very rare as a primary presentation, lymphoma can involve the lungs and cause these symptoms. It would typically be considered after other diagnoses have been ruled out and in the context of other systemic symptoms or findings.