I have a dull pressure in the head all the time due to a benign fibrous dysplasia bone lesion in my skull, and many times when I first stand up the pressure in my head increases so much that I can't walk or think, it just feels like my head will explode with every heartbeat (a forceful massive dull pressure every heartbeat), also this same pressure is felt in my upper chest at the same time. Eventually it fades from the center to the back of my head and dies out. If severe enough, my hearing briefly goes out. It follows the same pattern as near syncope upon standing, although I don't feel lightheaded at all. I also have non life threatening irregular heartbeats, but my heart and aorta is fine (I had a chest CT and cervical vessels MRI)