I just noticed, for some reason, I can't unlock any of the new shouts I've discovered, I have 18 available unused Dragon Souls that I can use but when I try to unlock a new shout it says "Dragon Souls are needed to unlock new shouts". The problem is I have a lot of Dragon Souls. I got this new shout that I really want to unlock and have before I head into Labyrinthian. Does anyone have any ideas as to why I can't unlock any new shouts?

This might be a dumb question but have you looked at the bottom left of your screen for the unlock option?
It's either unlock or learn I can't remember right now.
I know it got me for the longest time.I kept trying to use the shout but I had no dragon soul in it.

Not sure what the keybind is on consoles, but on PCs it's "R". Hover the cursor over the shout you want to unlock, press R, answer "Yes"....

It's the 'X' button on Xbox and I've already unlocked a lot of shouts in the game. It's just now it doesn't let me anymore.

Ah. No clue then.... call tech support?

I don't quite know what tech support would be able to do. It's probably some glitch I'm going to have to deal with until they fix it. Which would really svck because this game is almost based around shouts. If anyone else has any ideas I would love to read them.

Er.... my current (15th) toon isn't using shouts at all, because she's not doing the MQ period. She's not having any issues....

I play on PC so not sure about Xbox, but I had a similar problem awhile back. I remapped some keys and couldn't pick locks anymore or unlock shouts. I set mappings back to default and viola ... I was able to remap again after that to what I wanted and all was fine. Hope this might be the case for you on the Xbox.