sharp pain at back of head

Hello. The condition I am about to describe has been happening all my life. I am now 36 and can recall this happening since my childhood.

It always happens when I turn my head quickly or at a sharp angle. It happens randomly and over the years I could always count on it happening about once a year. If it happened on the left then within 6 months it would happen to the other side or visa versa. Then first side would happen again maybe a year later. I could always count on the opposite side happening within 4 to 6 months of the first side happening. But of lately it has been increasing with frequency it has begun to worry me.

The best way I can describe it is that if feels as if someone is jamming a needle or nail in the base of my brain at the back side of my skull. My vision instantly blurs, that side of my head and brain goes numb, the pain is sharp and severe and instant - and then I am left incapacitated for several minutes. As quickly as it happens it goes away - the pain doesn't persist - though the numbing and tingling affect does take several minutes to pass.

Again, this has been happening since childhood and I have always attributed it (or correlated it to) physical inactivity. If I stopped exercising playing sports, etc for a period of time and then got back into sports/exercising again then it would happen within several weeks of me picking things back up again. In the beginning I always thought it felt like a pinched nerve in my brain or a blood vessel bursting (without any medical knowledge whatsoever).

Over the last 18 months it has increased in frequency to the point its 3 to 4 months between episodes instead of the usual 12 to 18 months. Because its happened all my life I have always just assumed it was a normal thing - but because of its increased frequency it has begun to worry me.

Has anyone heard of these symptoms before, recognize what might be causing this or be able suggest what I might do.

Thank you.