I couldn't believe my ears when I heard my name called.
Would it be appropriate if I said
私? When is it appropriate to use
自分? What is the difference?
While the pronoun
私 has its own referent, meaning
自分 (in the Tokyo dialect) does not have its own referent, and it means
self. That is the difference.
In this case, it will be somewhat redundant if you use
私 in place of
自分 because there will be two different instances of the pronoun
私 referring to the same thing:
私 の名前が呼ばれたとき、 私 は自分の耳を疑った。
If you have
自分 in the adverbial-clause
自分 の名前が呼ばれたとき、 私 は自分の耳を疑った。
then, there will be only one instance of
自分 can anaphorically receive the referent from
私. That is more "economical" from a linguistic point of view, and is preferrable.
An analogy in English (not be taken so strict, due to the difference between the languages; in fact, there is a categorical difference) is the fact that
When John's name was called, John could not believe what he heard.
sounds somewhat redundant, and
When his name was called, John could not believe what he heard.