Headache While Working Out

Patient: Whenever I work out, specifically pull-ups, I get a really bad headache on the top of my head and I can kind of feel it in the upper part of the back of my neck. This only started about a couple of months ago. I took a one week break from working out and when I resumed again, the headaches didn’t return until about a week later. Do you have any ideas as to what’s wrong?