Acute Sinusitis: This condition is characterized by inflammation of the sinuses, often due to a viral or bacterial infection. The green nasal drainage is indicative of a bacterial infection, and the ear pain and sore throat can be referred pain or secondary infections. The combination of these symptoms makes acute sinusitis the most likely diagnosis.

Common Cold: Although the green nasal drainage might suggest a bacterial infection, it's also possible in the context of a severe cold, especially if there's a secondary bacterial infection. The sore throat and ear pain can be part of the symptom complex of a cold.
Allergic Rhinitis: If the green nasal drainage is not purulent but rather a result of chronic nasal congestion and inflammation due to allergies, this could be a consideration. However, the presence of ear pain and sore throat might be less typical unless there are significant postnasal drip and Eustachian tube dysfunction.
Influenza: Influenza can present with a sore throat and might be accompanied by sinusitis or other respiratory infections that could cause green nasal drainage and ear pain.

Meningitis: Although rare, meningitis is a potentially life-threatening condition that can present with symptoms like severe headache, fever, and stiff neck. In some cases, especially in children, it might initially present with nonspecific symptoms such as sore throat or ear pain. It's crucial to consider this diagnosis, especially if there are signs of severe illness or specific risk factors.
Lemierre's Syndrome: This is a rare but serious condition that starts with a sore throat and can progress to include symptoms like ear pain due to the spread of infection to the lateral pharyngeal space and internal jugular vein. It's essential to consider in patients with severe sore throat and signs of systemic illness.
Peritonsillar Abscess: While primarily causing severe sore throat, a peritonsillar abscess can lead to referred ear pain and, if the infection spreads, potentially cause sinusitis with green nasal drainage. This condition requires prompt diagnosis and treatment to prevent complications.

Wegener's Granulomatosis (Granulomatosis with Polyangiitis): A rare autoimmune disorder that can cause a wide range of symptoms, including sinusitis, sore throat, and potentially ear pain due to middle ear involvement. It's a diagnosis to consider in patients with persistent or recurrent symptoms that don't respond to typical treatments.
Tuberculosis: Although rare in many parts of the world, tuberculosis can cause chronic sinusitis, sore throat, and potentially ear pain if it involves the middle ear. It should be considered in patients with risk factors for TB or those who have been unresponsive to standard treatments for their symptoms.