Is It Paranormal Or Brain Tricks?

I figured since everyone else was asking paranormal questions I might as well ask too..I have been choked, slapped and not held down but felt as though I was being electrocuted in my sleep...the thing is it doesnt happen regularly it can happen a year apart and sometimes years apart...just curious to know if its a brain thing or paranormal thing. When I was slapped, you know when you're sleep but very aware of whats going on around you? Thats how I was and I felt a hard slap and I immediately sat up to slap the person back, thinking it was my sister, but my room door was locked and no one was there. I let the chocking thing slide because I had a dream that a dead relative was chocking me and woke up gasping for air. So i figured because of the dream that was why i felt that way. With the electricity thing, I was asleep and I felt myself vibrating rapidly, as though i was being electrocuted and both my sides (around the waist area) felt like someone was squeezing me really tight so much so that it felt really sore. The more awaken i became the more the vibration thing would simmer and eventually stopped..but it still felt as though someone was hugging my waist tightly and i was so scared i kept my eyes closed because i did NOT wanna open them and see whatever it was, and i eventually fell back to sleep and felt fine in the morning..