What the heck is this?!

I think theres something very weird happens when i meditate , yesterday i napped for 3 to 5 hours and i woke up normlly , i stayed awake 3 hours and went to meditate to astral project , what really amazing me is , i was meditating for around 1 hour and half ((( the time was too short because my mind was falling ))) and when i was meditating and i was very near to get the sleep paralyzes, my hand recieved a shock?! My right arm has jumped around 10 CM near me which made me open my eyes because i though someone hitted me , and when i meditated again in another day i got the shock on my right or left arm , or right or left leg , it happens only in one body part , what is this?? The second day i actually meditated for 40 minute without moving and having a good breath it started to shock again , then the shock stopped and the moment i nearly enter the paralysis again another part gets shocked and jumps  :o , what is that?!