Hi. First of all, allow me to thank you for taking the time to read this and maybe to answer me. I really appreciate it. I am writing to you in my try to identify what is happening in this almost round box that I m carrying on my shoulders. This is how it goes: For a lot of time (since I was a child) I ve been experiencing what is known as sleep paralysis . Actually there was a period of time (between ages 10 and 20 approximately) without any occurrences. For a few years now (about 4) I ve also been experiencing another interesting thing during sleep. Many times it starts as a sensation of free falling, but combined with sleep paralysis, so I cannot wake up completely instantly. Many times I felt that like a huge internal pressure/pain/force inside my head, but it is pretty different from what other people describe when they say they had the so-called blowing head syndrome . It is not like a very powerful sound, but it s more like a dynamite explodes in slow-motion inside my brain. Most of the times it was unbearable, so I was always trying (and finally succeeding) to move a finger or my hand so I could wake up from sleep paralysis (the more it took, the more it hurt). But then I ve tried not to do it (not to wake up), in order to see how far the pain can go. It turns out that this pain limits itself at some point, although the experience was far from pleasant the first time. Like I said, it starts with a feeling of free-fall, and then becomes an unbearable pain/pressure combined with the fact that I become conscious but cannot move. I also discovered that in time I kind of got addicted to this sensation and I m also able now to amplify it when it appears. I think the one of the best descriptions of the final, close-to-unbearable sensation is like someone is slowly pouring acid in my brain. The pain is so intense that sometimes I realize that I open my mouth to scream, involuntarily. When I manage to move and completely wake up, the pain disappears with a water-down-the-drain relaxing sensation. There is nothing else in real life that could help me describe it. The feeling of free-fall is close in nature, but nowhere close in intensity. In everyday life I m not affected. I m 29 years old and a doctor in physics (sometimes I blame that for my presumed brain damage :) ). Have you encountered anything else like this? Should I be worried? Thank you so much for your attention.