Thanks for your query at HCM! According to me you are suffering from migraine most likely as it is present on one side of hemicranium. It could be related to environmental and genetic factors and may be induced by triggers. Many things can trigger a migraine. These include 1. Anxiety 2.Stress 3. Lack of food or sleep 4.Exposure to light 5.Hormonal changes (in women) You need nutritional supplements and lifestyle alterations. Visit your local physician who may prescribe drugs like analgaesics, triptans or ergotamines for treatment. It is unlikely to be sinusitis. Don t take stress. Practice meditation as it may help you. Medicines can help prevent migraine attacks or help relieve symptoms of attacks when they happen. Take care.