BB Bold 9700 :: Freezes When Send/recieve Data

Randomly, my BB will start sending/recieving data (the rx/tx arrows constantly changing back and forth) and the entire phone will lock up. None of the buttons work, it wont respond to anything for about 2-4 mins. Then everything returns to normal. I notice it most in the facebook app or Viigo, mostly because thats when im scrolling a lot. Occasionally, the last button pressed will register after it wakes up from its coma, ie, if i press the back button when its frozen, and nothing after that, when it wakes up, it will *sometimes* register the button. I never get any messages or anything when its doing this.