May quest not completed even though I did everything

Do 5 for each of the towns (this is very bothersome at first because they each may send you to different cities, but it is best to get a quest from both of them to maximize your time), once you complete 5 in a city Devlin will give you a special quest. Complete
the special quest and (hopefully) that town will no longer be an option for future side quests (though I did find I was sent back to the town I had completed previously, but it was much less frequent).

I have Finn's Lute which I picked up by mistake by grabbing the whole chest full of loot but I don't have the quest yet. I can't even store it in my house. A question. I read in either the guide or the wiki that there is a quest in Markarth where you get
arrested and sent to the mine (I think this is the one) and everything is taken away even your quest items. It was advised that quests be completed before this as you don't get the quest items back though you do get everything else back. Is this a possible
route to getting rid of unwanted inventory clutter?

any1 here know why when i finished the main quest and i only got champion of cyrodil and all the other achievements havent been unlocked even though i did everything?

" I had that quest on my list, but then played OA and when I went back to Crowley he complained that I stole his property. I did get the 'quest completed' notice though..."

Yeah , something about picking up the T-51B from OA completes the quest.

I don't sell things that are unusual or have a name in it. My game has yet to mess up. But some quest items are stuck in my inventory even though I have already completed the quest. Though it's no biggy,