Let's say my friend is in my room and I am out in the kitchen.
At some time I decide to enter my room.
Is it appropriate to say おじゃまします when I am entering my own room?
It is not appropriate to use the phrase in that situation. 「邪魔{じゃま}する」 means "to bother", "to disturb", etc., which one would not be doing when entering one's own room.
A more suitable situation to say it would be like this. Suppose there are your good friend and his/her gf/bf in your room when you are somewhere else. As a joke, you might say 「お邪魔します」 upon entering the room.
Outside of comedy, you will basically never say 「お邪魔します」 in your own home, even including when entering your parents' or sibling's room.
answered Dec 14 '19 at 22:54
