Two questions, is this normal and is my house haunted?(rephrased)?

My house was supposedly built in the 1940's and it has the structure to prove it. Just today I was coming upstairs and at the top step I heard I was just trying to relax one day when I here knocking coming from my mothers closet. I have lived here long enough to tell the difference from an old house settling and something else. About 2 months ago a friend was staying the night so as I was coming up the steps behind her she was in my room. When I was setting up her bed I heard stomping up the steps. We were the only ones awake. But this story really stumps me, I shut my door. Ten minutes later I had to pee so I tried to open the door and the door knob kept on turning around and around and I was locked in my room! That was yesterday and it still is messed up! They are old skeleton key doors but my door could still be opened from the outside! Is that normal?