1. If the individual parts of the compound subject are joined by and, always use a plural verb. 2. If the individual parts of the compound subject are joined by or or nor, use the verb form (singular or plural) which will agree with the subject closer to the verb.
Headaches in the back of the head may be caused by a variety of ailments and injuries. Chronic headaches in the back of the head -- also known as occipital headaches -- are often variants of tension-type headaches or migraines. New-onset occipital headaches are a more urgent concern. Possible causes include blood vessel abnormalities, nerve disorders and serious traumatic injuries.
Cluster headaches are severe headaches on one side of your head that happen in groups, or clusters.. They usually occur over weeks or months. Cluster headaches can be so painful that you are not able to follow your normal routine or do your usual activities. The pain is often called the worst type of headache pain.