The left posterior side of the head paroxysmal pain is a headache in the posterior occipital region, mainly caused by the following reasons: 1. migraine, a common primary pain in clinical practice, characterized by episodes mostly on the lateral side, which can also manifest as moderate to severe fluctuation-like headache in the occipital region, and the headache can be relieved after rest and sleep. 2. symptomatic migraine, a headache originating from cerebrovascular lesions, such as ischemic cerebrovascular disease. 3. occipital neuralgia, located in the occipital region with paroxysmal Severe pain. The occipital nerve includes the greater occipital nerve and the lesser occipital nerve. Those radiating to the top of the head are usually the greater occipital neuralgia; those radiating to the nipple are usually the lesser occipital neuralgia. It can be treated with high dose of vitamin B12 orally.3. Cervicogenic pain, headache caused by excessive tension of neck muscles, can be treated with neck massage and hot compress.4. Phytodysfunction, patients may have poor mental and sleep status, and some anxiety and depression symptoms, which cause occipital pain. These are the causes of posterior occipital pain.