That happens to me all the time, and it's pretty much what you describe. It just takes me a long time to recall information about a topic. My mind just works that way. I simply can't just pull up the information very quickly. I hate this, because I have a very good memory. It's just really, really slow.
It is not a problem at work. Generally, I can can come up with enough of an answer and then I say that I have to think about it for a while and I'll get back to them later. I hate it when some people are so impatient that they need an answer right away, because then I have to rely on stalling tactics: "That's a good question. A very good question. Yes, indeed, an outstanding question."
It's much more difficult in social situations. It's a lot harder to postpone answering, and people don't understand why it takes you so long to respond. Also, in social situations, the questions tend to be more open ended, which makes it harder to bring up the necessary information. There is just so much that could be relevant.
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"Like lonely ghosts, at a roadside cross, we stay, because we don't know where else to go." -- Orenda Fink