You have a great phone and a great plan there! I can certainly let you know how to utilize that great Mobile Hotspot feature on your 8X!
Take a look here http://bit.ly/RzVfvO. I believe this is what you were doing. If this isn't working, please turn the device off, pop out the SIM card and then pop it back in. Power back up after about 30 seconds and then see if it's working. There may also be something in your plan that was not added correctly because the hotspot is included. You can contact tech support at 800-922-0204 for more help with that.
Please follow us on Twitter @vzwsupport