Just starting happening about 5 weeks ago. Doing a plank at gym and when came from it, I had a sudden headache. Mainly, on the left side. Continue with exercise and it faded. Now, every time and go to gym and start with plank or whereever I an exerting alot of pressure, I just a throbbing headache on the left side. I am breathing thru the exercise and we had elevated me on the planks but its still happening. This is starting to scare me. My doctor said its an exertion headache... I am not sure. It is a little frightening since I have never had it before. Your thoughts