KB31857 How to setup and manage a Mobile Hotspot Connection
As you see, there are two requirements for the Hotspot function -- BB OS 7.1 as well as a service plan, from your mobile service provider, that enables it.
Occam's Razor nearly always applies when troubleshooting technology issues!
If anyone has been helpful to you, please show your appreciation by clicking the button inside of their post. Please click here and read, along with the threads to which it links, for helpful information to guide you as you proceed. I always recommend that you treat your BlackBerry like any other computing device, including using a regular backup schedule...click here for an article with instructions.