Boom Boom,
What's up Bro? I haven't seen you since the bodybuilder.org site folded up man. My handle over there was IronLfter. Anyway man, I know what you mean about these fucking headaches. I used to have the exact same problem and it would come and go. Thank goodness i haven't had the problem in a year or two.
I used to be the same way...would be fine all day and start my workouts and bam!! The pain would kick in on my first intense set...especially if it was bench, squats, deads or chins. I would force myself through the workout and would even tie a rag around my head as tight as I could ( I looked like I was trying to be fucking Rambo or something) to cut off the circulation and the throbbing. I could feel my temples throbbing against the rag. I know that wrapping something that tight during a workout probably wasn't wise, but I was so pissed about the pain interrupting my workouts that I would do anything to get through them.
During this time I also noticed the pain would come on during sex too. It seemed that any physical activity would bring on the headaches. Hell, I would have an orgasm and then would feel like my brain was going to explode man.
I seemed to notice the occurence of the pain decreasing when i stopped doing dumbell flyes. I think my problem was a pinched nerve and it seemed to be stimulated by doing flyes with dumbells.
This may not be of much help to you Boom Boom, but maybe there is a certain exercise that is causing this for you too. If you can isolate which exercise it is then maybe that would help. Anyway, bro I just wanted you to know that you aren't the only one out there who has had this problem. Best of luck to you and take care.