Oh, is it that you're embarrassed about being called by name, maybe?
Literal
Ah, maybe name [object-を] be-called [nominalized-の subject-が] embarrassing [quotative-って]?
Ending in って with rising intonation turns the sentence into a soft rhetorical question — 'is it that...?' / '...I mean?'. The passive 呼ばれる frames the speaker as the recipient of being called by name, removing the need to specify who's doing the calling. もしかして ('by any chance', 'could it be') softens the inquiry into a tentative guess.