"Is this my bread?"
In French, there are 3 ways to ask a question:
1) Most formal: when the verb and the subject are inverted (the verb is in first position)
Est-ce mon pain ? = "Is this my bread?"
Here, you have to put a hyphen between the verb and the subject in French.
2) Less formal: when the subject is in first position and the verb in second position
C'est mon pain ? = This is my bread?"
3) Idiomatic phrase: "Est-ce que" (literally "Is it that"), or "Est-ce qu'" (before a vowel)
Est-ce que c'est mon pain ? = "Is this my bread?"
You can probably say "Est-ce que sa c'est mon pain?". But C'est mon pain is more like, "That my bread?"