I get these terrible headaches on the right side of my head and for the duration of my headache my right eye goes a little droopy. I was getting them weekly or so and then I had one last night and decided to try and get to sleep early. But I am having another one today. I have had them for as long as I can remember. The pain is right in my forehead and right at the back of head above about an inch above my neck. It is only ever in the right hand side of my head
Sounds like a migraine, the droopy eye is a symptom that I have with autonomic migraines. Check out the internet for a headache diary and start keeping one to document the symptoms and possibly triggers. The person to see about this if is serious is a neurologist.