Cluster Headache: This diagnosis is the most likely due to the specific characteristics of the headaches, including their location behind one eye, short duration (15 minutes to 2 hours), and associated symptoms like tearing from the same eye and facial fullness. Cluster headaches are known for their severe, unilateral pain and are often accompanied by autonomic symptoms such as lacrimation (tearing) and nasal congestion.

Migraine: Although migraines can present with unilateral pain and last from 4 to 72 hours, the short duration and specific pattern of symptoms (like tearing from one eye) might distinguish this case. However, migraines can have a wide range of presentations and should be considered.
Trigeminal Neuralgia: This condition involves sudden, severe, shock-like pain around the eyes, lips, or nose mainly because of abnormal blood vessels pressing on the trigeminal nerve in the head. While it doesn't typically cause tearing, the intense, unilateral pain could be a consideration.

Temporal Arteritis (Giant Cell Arteritis): Although less common in a 22-year-old, this condition can cause severe headaches and should not be missed due to the risk of vision loss. However, it typically presents in older adults.
Cavernous Sinus Thrombosis: A rare but potentially life-threatening condition that could cause headache, facial pain, and eye symptoms due to a blood clot in the cavernous sinus. It's crucial to consider this due to its severity and the need for prompt treatment.
Pituitary Apoplexy: A medical emergency where a pituitary tumor suddenly hemorrhages or becomes infarcted, leading to severe headache, visual disturbances, and potentially life-threatening hormonal imbalances.

Sphenoid Sinusitis: Infection or inflammation of the sphenoid sinus can cause deep, severe headaches that are often described as behind the eyes. It's less common but could be considered with appropriate symptoms and findings.
Raeder’s Syndrome: A rare condition characterized by a combination of facial pain, ptosis (drooping eyelid), and decreased sweating (anhidrosis) on one side of the face, which could be considered if the patient presents with additional specific symptoms.
Paratrigeminal Syndrome (Raeder’s Syndrome Type II): Similar to Raeder’s Syndrome but with additional symptoms like tearing and redness of the eye, which might align with some of the patient's symptoms.