Can't use apps outside of my house? - 1

Ever since i changed my Sim card on my IPhone 4S I have had a problem.

Basically, whenever I'm without a WI-FI connection, I can't use any of my Apps that require an internet connection such as Facebook, Twitter, WhatsApp etc…
I have checked and my 3G ( Cellular data ) is enabled.
I have no idea what to do. Any help would be appreciated!

Thanks!

Added (1). Yes i do have a data plan

Do you have a mobile data plan on the new simcard?