I see realistic dreams with my exact room settings why does it happen?

[Hoquen]

Many of the times I have noticed that my dream would take place with the exact setting as my room when I went to sleep. However the dream will be so realistic due to being in my room setting I wouldn't know I'm asleep would think I'm awake. Once during my sleep felt like someone was trying to behind me trying to wake me up with everything in its place with the light on ( I keep light on due to seeing such dream with exact setting) but  I was thinking not possible my room is locked how did anyone get in. But I couldn't get my self up within the dream setting. Then in real I woke up after a bit to see no one in room.

Similarly another time I seen in was sleeping in dream with someone in room sitting. And told the person to sit beside me. As the dreams seem real during it is hard to distinguish if real or unreal. Until I wake up to see it was dream.

One incident was when taking nap my parents called me for dinner in real life but I was still sleeping. However, I was dreaming which I didn't know it was dream till later, that I got myself up somehow but body was not moving properly. And I could hear my parents speak at their dinner table. In dream not in reality. In the dream after getting off the bed moving two steps I couldn't move anymore something happened to my leg or muscle. So I called my house number which I see calling on speed dial in the dream. And my parents saying whose calling now will see later as they were eating. Then min later I actually wake up to see it was dream.

Why does this happen? Such real dreams? And common factor is none is positive dreams. And exact setting to the point if light off then dream will be with light off. I also toss and turn lot and kick in sleep.

If you know reason behind this please let me know thanks.