I am another one who suffers from this strange condition. I am 28 years old and I come from Greece (so forgive my language errors english is not my native language).
My symptoms are just as 7ducks described them, except I also have this constant low buzz in my left ear which appeared along with the condition and is always there. I also seem to periodically manifest a few symptoms not mentioned here like a sense of "fever" or a "burning head" in a way, head "pressure",very mild palm/hand/leg numbness, fatigue/sleepiness and some times very low fever (37-37.5 celcius)
A major difference than you guys is that I seem to be lucky so far as the condition comes and goes after 1-2 months. So the symptoms I described above may only be noticed by me as i keep going "in and out". But other than that I would say 7ducks' description is very accurate for how i feel like most of the time when i have the symptoms.
My first "crisis" was in 2002, which lasted a 2-3 months. It started along with a case of a Epstein Barr Virus (EBV - sort of very tough flu). The virus was found after the dizziness was gone (after a very long series of tests - including head cat scan) and the doctor said that the virus seem to have infected the liver and that was the source of the problem. So that stayed there. I had another case that summer which lasted 1 month, then I had no problem up until spring 2005. It came back with a very tough case in 2005. I started tests again and that's when I was diagnosed woth a cervical syndrome case. Because my knowledge of english medical terms is bad i'll just copy/paste from a medical site:
"Cervical syndrome is a term covering several conditions of the cervical (neck) area.
Cervical spondylosis involves degeneration of the cervical vertebrae (the seven bones making up the neck region of the spine). This is basically osteoarthritis of the neck. Cervical spondylitis is inflammation of the synovial joints between the cervical vertebrae. Nerve-roots originating from the neck area may also become irritated. Symptoms may include pain felt from the back of the head to the top of the shoulder blades, pain radiating into the arm, and numbness in the hand. There may also be problems moving the neck.
Treatments may include heat, cervical traction, immobilisation and physiotherapy.
Cervical syndromes are common in people who perform repetitive motions of the shoulder or have to maintain a fixed neck position while making repetitive motions of the hands."
I have a degeneration betweehn A2-A3 (3rd vertebrus from the top). Not all orthopedics agreed about this being the cause back then. Again the results came after I was starting to recuperate. I was also diagnosed with anxiety/stress but I was certain it was a symptom and not the cause, as most of you guys confirm. So took a long summer vacation along with anti-inflamation and muscle-reluctant pills and it gradually went away (not sure of the medication helped)
In spring 2006 I had another case and since i was already leaning towards the cervical spine, i went to a friend of mine who teaches physical fitness in the local university. He is an expert in treating athletes with injuries. We had sessions which included physiotherapy and upper body building. He says that cases like that need very strong upper torso muscle system to keep thins in place, especially in my line of work (I am a software engineer/programmer so i spend lots of hours in front of a pc).Symptoms went away again, then back for two short spells in autumn and early this year. They are back since 10 days ago which why I started looking around the net and found you guys.
Other facts I would like to note are that the symptoms always seem to start after a low feverish condition (or high fever in a couple of cases) and eve a common cold(soar throat etc). The condition seems to always come during times of high shycological and physical stress. Caffeine seems to affect in a negative way. Also driving seems to make me feel worse.
Concluding, I'd say that looking around the net I found some cases of cervical syndrome can maniffest as what we experience, which include artery blockage as someone proposed among other things, though from what I read I cannot be conclusive. Personally I acted as if that were the case with muscle reluctants and excersise but I am not sure if the cure worked or if it simple went away like the first two times. I will look into it more in the next few days so I'll keep you posted as soon as I have something new.