I looked at the Razr owners manual and there is no mention of an icon like that in the manual. My guess though is that is is probably the network extender that I mentioned above. You probably have a neighbor that has one and your phone is connecting to it. If I recall correctly, you are not charged for data if you are connected to one.
Try this, take a walk or drive down the street and see if the icon goes away. If it does, then it is most likely a range extender.
Also, if you are concerned about data charges, you are not charged for data that is downloaded over wifi. So if you are at home and connected to your wifi network (or any other one for that matter) and download something, it does not count against your monthly 4G data.
David