Why do I only get headaches in the back of my head?!

You don't have any spine in your neck area or if you do you have big problems. The reason for the pains in the back of your head is that headaches are caused by tight neck muscles, they go to the top of your head where they connect to muscles going around the head. When the neck muscles get tight they pull the head muscles into pain as well and that's your headache. Your pains are coming right from the neck muscles. To get rid of the pain you have to free up your neck muscles and here's how to do that:
Neck
Put your hands alongside your head so your thumbs are on the front of the muscle under your ear and your fingers are on the back of the muscle behind your neck. Squeeze your thumb and fingers together and hold. Relax your body. When your fingers and thumb touch, about one minute, slowly lower your head as far as you can, release the pressure but hold your neck lowered for another 30 seconds.
For best results relax your body first by taking a deep breath and exhaling then remain this relaxed.

Yes it is normal (in the sense that it is a common thing). It is migraine. You might have problems with your spine in the neck area.

http://www.vagra.ru/

They're probably tension headaches, from your neck and shoulder muscles tightening up. I get them too.