Are there times where there is something that would be painful to admit, but you don't realize until later that it was weighing on you?

Yes, of course. Sometimes I'm too focused to notice in the moment.

Focus (actually trying to perform well at a given task) has its advantages. Maybe it's possible to train (or cue with some external trick) brief moments of global or introspective thinking, but quickly returning to the flow if adjustment isn't needed. Probably there's both a trade-off and a happy medium.