Is this brain promblem?

i'm afraid to ask my mother about this, so if someone can answer me, it will help me. for some time I noticed that every time I get up from my bed, I get dizzy and can't see anythig for few seconds. and if I have my head in one possision for long time, back of my right side of my head starts to bern. I am afraid that somethig is wrong, so if someone have any idea what can this be, please tell me.

Check your blood pressure. When someone with ultra low blood pressure sits up or stands quickly, the blood drains from the brain causing a temporary dizziness.