Ice Pick Headaches From Shadow Boxing

I used to shadow box very often, and when you punch your head moves just a little... Well after a long time of shadow boxing I would get a very sharp stabbing pain on the spot every time... I stopped for a while and hit the heavy bag and after going at it for a few minutes a particular punch gave me a bad ice pick headache, I havn't shadow boxed or hit the heavy bag for a few weeks now, but i'm pretty sure the condition isnt gone, I think its an ice pick headache problem... But what concerns me is that it only happens when my head moves, although rarely I do get a much smaller pain on that spot from doing nothing. Couldn't find anything online that connects ice pick headaches to head movement, and i'm concerned that I could have damaged my brain from all of the shadow boxing( I did it alot as I used to be fat, I did it so often then i'm now in good shape and pretty toned)