This is directed to the sharp pain shooting through the head. I was getting the same pain, it last 3 to 5 seconds, stops and 5 to 10 minutes later it happens again. I work as a banquet server, lifting 25-60 pounds a day. My issue was related to the stress placed on my shoulders and neck. I suffer from what I call a pinched nerve. The only way for me to get rid of the sharp pain was to be manipulated (spinal/neck). Also, as one of your guest stated, problem with your sinuses can also have the same adverse affect. If that is the case, I find that Dimetapp (Cold & Allergy) during the day and a Zyrtec at night takes it away.