What Causes Headache?

hi doctor,

am 39 years old.. work as a manager(no physical activity), o- blood type, 104 kg. , 182cm tall..

I have a slight headache in the lower back of my head since a week, I had a blood test which shows my BP is 145/100 then it came down to 140/95...

no cholestro, no triglisoride..

and I need to bring it back to the normal BP, is there any way to do that.

thanks in advance