One side of the headache eye pain may be migraine, glaucoma, painful eye muscle paralysis and other diseases. 1. migraine: it is a chronic vascular headache due to various reasons, especially genetic factors, manifested as severe headache, mostly occurring on the side of the head, which will involve the eye socket. 2. glaucoma: it is caused by the increase of intraocular pressure due to the abnormality of one of the links in the atrial fluid circulation, resulting in optic nerve atrophy and visual field defects, which will cause eye pain, and in severe cases, it will involve the same side of the head. 3. Painful ophthalmoplegia: It is an idiopathic inflammatory condition that occurs in the cavernous sinus and supraorbital fissure, and is a total ocular muscle paralysis with a painful onset. Symptoms of the disease are usually evident within two weeks with eye pain and drooping eyelids accompanied by headaches. One side of the headache eye pain may also be seen in head tumors, cluster headache and other diseases, if the symptoms of one side of the headache eye pain, persistent unrelieved, need to promptly seek medical treatment.