I have been trying to open my third eye via using sound, I lay down or sit and in pitch black listen to sound vibrations off YouTube, I actually fell asleep during it recently and woke up and the middle of my head where the third eye is located was vibrating, I thought it was my muscle twitching but when my touched my head my muscles were relaxed?

Is this normal? And is it bad I fell asleep?
I also had a feeling of dread which went away very quickly, I now sometimes see black shadows and the such is that strange however after reciting power words of certain aspects of Marduk I know longer see these black things lol..