2 This is the only relevant part of the answer.
source | link

I was having the same problem of not being able to equip my shield or a bottle. I read all the answers and they all give the general instructions on equipping an item. However, nothing was working. I opened one of the other games in progress and had no problem equipping the shield or bottles. I finally called Nintendo tech support to ask if there were any known glitches with the game. Sasha (Nintendo Tech Support) said he hadn't heard of any, but checked the database. He found a post that said ifIf you are carrying the "Cursed Medal" in your pouch your pouch items are inaccessible. You must store the cursed medal at the claim check in the bazaar on skyloft. I hope this helps others out there that may still be playing this awesome game.  

I was having the same problem of not being able to equip my shield or a bottle. I read all the answers and they all give the general instructions on equipping an item. However, nothing was working. I opened one of the other games in progress and had no problem equipping the shield or bottles. I finally called Nintendo tech support to ask if there were any known glitches with the game. Sasha (Nintendo Tech Support) said he hadn't heard of any, but checked the database. He found a post that said if you are carrying the "Cursed Medal" in your pouch your pouch items are inaccessible. You must store the cursed medal at the claim check in the bazaar on skyloft. I hope this helps others out there that may still be playing this awesome game.  

If you are carrying the "Cursed Medal" in your pouch your pouch items are inaccessible. You must store the cursed medal at the claim check in the bazaar on skyloft.

1
source | link

I was having the same problem of not being able to equip my shield or a bottle. I read all the answers and they all give the general instructions on equipping an item. However, nothing was working. I opened one of the other games in progress and had no problem equipping the shield or bottles. I finally called Nintendo tech support to ask if there were any known glitches with the game. Sasha (Nintendo Tech Support) said he hadn't heard of any, but checked the database. He found a post that said if you are carrying the "Cursed Medal" in your pouch your pouch items are inaccessible. You must store the cursed medal at the claim check in the bazaar on skyloft. I hope this helps others out there that may still be playing this awesome game.