I m not sure what is happening and I do admit that I am under quite a bit of stress; however I feel like there is a sensation of electrical shock zaps going off in my mind just at the point where I relax and drift into REM . This is so powerful that I jerk myself awake. I am healthy otherwise but the sensation is frightening
Hi, it appears to be the headache during the sleep, probably due to the hypertension, anxiety, tension, etc. I advise you to consult a physician for diagnosis and treatment.  Practice yoga, meditation, reading books of your interest, and to hear music. Thank you.