Viral Upper Respiratory Infection: This is a common condition that can cause headaches and a feeling of warmth, possibly due to a low-grade fever. The recurrence of headache over two days could be part of the natural course of a viral infection.

Tension Headache: This is a common type of headache that can occur due to stress, fatigue, or other factors. Feeling warmer could be subjective or related to environmental factors.
Migraine: Although migraines can be severe, some individuals may experience milder forms that could be accompanied by a feeling of warmth or slight fever.
Sinusitis: Inflammation of the sinuses can cause headaches and a feeling of warmth, especially if there is an accompanying low-grade fever.

Meningitis: Although less likely, meningitis is a serious condition that can present with headache and fever. It's crucial to consider this diagnosis, especially if the headache is severe and accompanied by other symptoms like neck stiffness or confusion.
Encephalitis: Similar to meningitis, encephalitis is an inflammation of the brain that can cause headache, fever, and altered mental status. It requires prompt medical attention.
Subarachnoid Hemorrhage: A severe headache (often described as "the worst headache of my life") could be indicative of a subarachnoid hemorrhage, especially if accompanied by fever or other neurological symptoms.

Temporal Arteritis: This condition, more common in older adults, involves inflammation of the blood vessels in the head and can cause headaches, fever, and other symptoms like jaw claudication.
Brain Abscess: A rare but serious condition where an abscess forms in the brain, potentially causing headache, fever, and neurological deficits.
Systemic Infections: Certain systemic infections (e.g., endocarditis, osteomyelitis) could present with headache and fever, although they would typically be accompanied by other specific symptoms related to the site of infection.