Suggest Treatment For Headache

hello, so beginning last night I developed a small headache, thinking I was dehydrated I started to drink a lot of water which helped. after that it was only everytime I moved a certain way for went from sitting to standing or just bending down and back up again where I now even today its a sharp pain like a knife just peircing through the right back side of my head and the pain travels to but not as bad to behind my right eye. I can still feel pain while not moving its easily unnoticiable compared to when I move my head.