Thank you for posting your question.
The headache and surge is probably due to increased blood pressure. If this is something that you have never experienced, before, perhaps your blood pressure is somewhat elevated, and when you bend over it increases more. causing symptoms.
This is a fairly normal sensation. Some people tend to breathe improperly when they bend over, and this can contribute.
I would suggest you start with a blood pressure check. If you have further questions, please contact me.
IF I HAVE ANSWERED TO YOUR SATISFACTION, PLEASE PRESS ACCEPT. FEEDBACK IS APPRECIATED.