Are all doxie's so shy?

My Elijah has been my constant 24/7 companion since he was four years old. He loves to play with one other dog Simba, a Boxer mixbreed, and he adores any and all Cats, even when said cat wants nothing to do with him.

I have never been physical with Elijah, ever, when he is misbehaving I tell him he is going to get a spanking, and the behaviour stops. Even tho I have never actually "spanked" him, he fears it so much he freezes instantly. Also, when trying to play chase games with him, he will freeze in place, tuck tail between his little legs, and literally just stop everything.

Elijah gets an overload of affection as it is just the two of us alone together all of the time. I just don't understand this "freezing" seemingly fearful responses to me.

I can't even hardly raise my voice and he adopts a fearful stance with me. Anything I can or can't do that can help him be more confidant?