Why Do I Have Pressure Sensation In Head And Neck With Muffled Hearing?

I have suffered from a variety of symptoms that seem to be connected. Sometimes, upon standing, or when turning my head, or when lying on my stomach, sounds become very muffled, I can hear my heartbeat in my ears, I feel slight pressure in my head and neck, and I hear a high-pitched, almost inaudible ringing. Thes all seem to happen simultaneosly, then subside after a few moments, though oftent the pressure and pain in my neck and head stays.