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.
A characteristic of tension headaches is that pain usually occurs on both sides of head and is in the form of a dull, steady ache. Cluster headaches are rare, extremely painful and debilitating headaches that occur in groups or clusters. They often appear during seasonal changes. They are also described as suicide headaches, a reference to the excruciating pain and resulting desperation that has sometimes culminated in actual suicide.