When your cursor is hovered over a barrel, body, wardrobe, chest, desk, etc, the computer may think you want to 'store' your items IN that object. Which, of course, you don't.
My advice? Stop dropping things. Sell them. You need money! It costs 5000 to get a house in Whiterun. Sell these items and buy a house, which is the ONLY way to guarantee you can store items safely. There is a chest in the bedroom of that house which will hold all your items without ever losing them.
If you want those items again, just buy them back later for a little more money. Believe me, money is NOT a problem in this game. I'm level 36 and have 57k without even looting bodies anymore

Just be patient and stop dropping stuff
