Hello. When Lying On My Stomach (any Duration Longer 10

Hello. When lying on my stomach (any duration longer 10 minutes) and then rise into up position. I began to start a headache which last no more 20 minutes .Headache than gone. Im fine. The other time I've noticed Is sorry to get dirty but doggy style sex will also bring on headache, when standing back into uprise from first position (lying) Only when . I can stay laying down no headache Just when laying down then going into up right position