First of all, I do not expect to get a helpful answer at all, but I figured there's no harm in trying. This thing is a mystery. Please read!
I'll start off by describing the sensation: There is no pain and no real visual disturbances*. It's kind of like what I imagine a horrible (but not too intense) drug trip would be like. They occur instantly, like something in my brain throbs or pulsates (once) aggressively, then again, then again.. With less intensity each time, about 4-6 times (over the course of about 5 seconds altogether). I consider this the beginning. Things then calm down in my head, but then I start to feel an uncomfortable sensation of something building up. And what this sensation is building up to, is another throb. This process then repeats itself over and over for anything from 3 minutes to just over an hour (I'm not entirely sure how long the build up to throb process usually lasts, 1-3 minutes I'd say). The change that occurs throughout the course of each episode, is that towards the end, I sometime think it's gone. But then I get the sensation of the build up (It's very subtle to begin with, this sensation) again. I find that part very frustrating, because I usually think 'okay, it's gone!' But it's not. Eventually, during the build up sensation, it'll quickly dissolve/fade away and I'll be back to normal again. I usually concentrate on what sensation I can feel, just to make sure it's gone.
*If I were reading, a throb would normally make me lose my place.
I can get an attack when I'm watching TV, playing guitar, listening to music, studying, reading, playing sports, drunk (I'm more inclined to get distracted and forget I have one when I'm drunk), sleeping (They wake me up), whatever. I am sure there is no obvious trigger, if there is any trigger at all. They are completely random.
I used to obsess over how long one would last, because it's usually a fair indication of when the next one will occur.
I'm 20 years old now, and I've been getting these 'head attacks' since I was 12. Back then, I thought I was dying and they were the scariest thing in the world. Years of anxiety and psychological trauma followed (nothing too severe - I can go into detail here if needs be). I was at my worst during bouts of these attacks. I've been depressed, anxious and just plain freaked out by them, but I've learned to live with it. It took so long, but I'm in a safe state of mind now. It's still extremely unpleasant and a giant pain in the **s though.
They used to occur randomly over the course of 2 weeks (USUALLY 2 a day) over a 9 month period (these are approximations). The odd time, I'd get a random one. Although the attacks themselves have not changed, I've been getting them pretty much everyday since February 2009 now, every 2 or 3 hours.
I have been to doctors, neurologists, hopsitals, hypnotherapists. I have had EEG and ECG scans. There is no physical thing inside my head. I am not dying.
Diagnosis' that have been pondered were vertigo, migraine associated vertigo, ocular migraine etc. Nothing I have ever read describes what I feel. I call them 'migraines' due to my mother suffering from classic migraine when she was my age, but I have no idea what they are.
By the way! I have been prone to headaches my entire life. Perhaps that's unrelated, but just in case..
If you took the time to read this, thank you very much, if I gain any more insight to what is wrong with me, I will be on top of the world!