What causes pain behind the left ear and at the back of the head?

Generally, pain in the back of the head behind the left ear may be caused by factors such as lack of sleep, inflammation of the lymph nodes behind the ear, or occipital neuralgia.

1. Sleep deprivation: Poor mood, excessive mental stress, or irregular lifestyle habits can lead to insufficient sleep duration and poor sleep quality. As a result, the brain does not get adequate rest, which may trigger cerebral dysfunction. This condition is often accompanied by symptoms such as occipital headache, limb weakness, and general fatigue.

2. Postauricular lymphadenitis: Local inflammation may cause redness, swelling, or pain at the affected site. Inflammation of the lymph nodes behind the ear may lead to swelling and pain in surrounding tissues, potentially radiating to the head and causing headaches. Examples include postauricular lymphadenitis secondary to external otitis, otitis media, or scalp infections.

3. Occipital neuralgia: If the pain is episodic rather than continuous and there is no obvious local tenderness, it may be due to occipital neuralgia. This condition is primarily triggered by excessive fatigue, sleep deprivation, fever, or exposure to cold, leading to dysfunction in the regulation of subcutaneous nerves in the scalp. It typically presents as intermittent sharp pain behind the ear and at the back of the head, possibly accompanied by upper limb numbness and weakness, as well as discomfort in the neck and shoulders.