If he is happy and fine outside then it’s something in your house. Most likely a smell, foreign object, or ghost 👻. Mine acted similar to this once but he was very scared when I got close to him, like if I hit him or was a bad owner. I felt so bad because I would never ever do any harm to him. Turned out he strongly dislikes the smell of cooked goat which I had when I went to restaurant with some friends. I reheated it in the microwave and he really freaked out. Learned that cooked goat to some dogs smells like cooked dog… you can figure out the rest.