How can I get more information on Miscellaneous quests in Skryim once they are in my journal?
Solution 1:
I don't think that there is any additional information in the quest journal about Miscellaneous quests (that is, specifically the quests that get filled under the "Miscellaneous" category in the journal). The one line in the journal is all you get.
(Which, yes, is a surprising choice on Bethesda's part. Most RPGs will give you a paragraph or two about any quest in the journal, but Skyrim seemingly doesn't for Miscellaneous quests.)
However, if you've forgotten the context of the quest (which, as you point out, is very easy to do), you can always turn on quest tracking for that individual quest. Make sure that quest tracking is turned on for the Miscellaneous category as a whole (in the left column), and then turn on quest tracking for the individual quest in the right-hand list. (And maybe turn off quest tracking for other quests.)
Also, don't forget that you can select a Miscellaneous quest and get a map location for that quest.
These will let you at least find the person, place, or thing for that quest, even if you can't recall why or what you need to do with them. In almost all cases, what you need to do becomes clear when you get to the person, place, or thing.
Solution 2:
You have probably activated all of the individual misc quests that you want to do, but you've forgotten one thing.
To be able to view the individual quests, you need to ALSO activate the larger quest (miscellaneous) which is located in the same layer as all the main quests.