Viral Upper Respiratory Infection (URTI): This is the most common cause of cough, congestion, and ear pain, especially given the duration of 4 days. The symptoms are typical for a self-limiting viral infection that often affects the upper respiratory tract and can cause secondary ear pain due to Eustachian tube dysfunction.

Acute Sinusitis: Often presents with nasal congestion, cough, and facial pain, which can sometimes be referred to the ears. The symptoms can overlap with those of a viral URTI, but sinusitis might have more pronounced facial pain and purulent nasal discharge.
Acute Otitis Media (AOM): An infection of the middle ear that can cause ear pain, fever, and sometimes cough if there's associated postnasal drip. It's a common complication of URTIs, especially in children, but can occur in adults as well.
Allergic Rhinitis: Can cause chronic or seasonal symptoms of nasal congestion, cough (from postnasal drip), and sometimes ear fullness or pain due to Eustachian tube dysfunction. The history would typically include exposure to allergens and possibly a seasonal pattern.

Pneumonia: Although less likely with the primary complaint of ear pain, pneumonia can present with cough and can be associated with pleuritic chest pain that might be referred to the ear. It's crucial to consider, especially in vulnerable populations or those with severe symptoms.
Epiglottitis: A severe, potentially life-threatening condition that can cause sore throat, difficulty swallowing, and sometimes ear pain due to the proximity of the epiglottis to the ear. It's less common but critical to diagnose early.
Lung Cancer or Other Malignancies: In rare cases, persistent cough and other respiratory symptoms could be indicative of a malignancy, especially in smokers or those with a significant smoking history.

Tuberculosis (TB): Can cause chronic cough, among other symptoms, and is considered in individuals with risk factors such as immunocompromised status, recent travel to or from areas with high TB prevalence, or exposure to someone with TB.
Relapsing Polychondritis: A rare autoimmune disorder that can cause cartilage inflammation, leading to ear pain, among other symptoms like respiratory issues. It's a diagnosis of exclusion and would require specific findings like cartilage destruction.
Wegener's Granulomatosis (Granulomatosis with Polyangiitis): A rare autoimmune disorder that can affect various parts of the body, including the respiratory tract, and cause a wide range of symptoms including cough, sinusitis, and ear symptoms.