Cellular data problem

[Edster]

Over the last month, I have been required to purchase additional data well above any previous month. I know that there's plenty of possibilities for this but my usage was no different than any of the previous months. I listen to Pandora, I download some books and games and an app every now and then. The only thing that was different was that there was an update to Pages that seemed to never happen. I would get an error message that said that it couldn't download. However, the little "progress" box stayed open and the icon was in that "grey" mode that appears when you're downloading something.
I guess the question is: Is there somewhere that I can go to see if something is openor running that's using data on a continual basis?