What Causes Episodes Of Pressure In Head,dizziness And Numbness In Arms?

I have constant pressure in my head. Not the slight dizziness when you get up too fast, but it comes on suddenly when I stand up, get out of my car, turn around - starts with getting all cold over my head and neck, vission goes funny (like looking into the sun), then the pain comes on - really bad (on a scale of ten a 9) in my forehead, roof of my mouth, right eye and shooting down the sides of my neck. Then my arms go numb and start throbbing. Nausea is sometimes involved. The frequency and duration of these episodes have been increasing. On top I don t sleep - around 2 - 3 hours per night because of the pressure in my head lying down is a struggle. Don t feel like eating, but I drink lots of fluids.