I have severe headaches in only my right side of my head and the pain goes down in my neck and into my arm why could this be? I get severe headaches in the right side of my head only, the pain is in my temple, behind my eyes, down the right side of my fac

Cluster headache? One possibility is a cluster headache. It is normally on one side of head. Severe pain eye and temple region. It repeats on timely manner like clockwork. Not common. There are some meds that may help. Talk to your md.
There . There could be multiple causes to the type of headaches described here. They are dependent of patient's age, sex, and chronicity. For instance, in younger folks these can be migraines; and for older people they may represent a vascular or inflammatory condition. Therefore, the first order of business should engage a full medical and neurological evaluation by a doctor. In addition to a physical examination, the physician will have to determine if lab tests and/or imaging studies like MRI are necessary. Delay in seeking medical attention in your case may carry catastrophic consequences.