Common cases of frequent headache are stress, lack of sleep, over thinking. Episodic headache is most frequently due to migraine. So assesses your frequency and severity of headache and its associated features such as nausea, vomiting, headache getting worse by loud noise or bright light. Also watch for your sleep pattern. Are you worried or stressed about something. Has something bothering you for a little while. If you find that your headache is mild and is frequent then try to reduce your stress level or take some help from a psychiatrist.