When you click on a story in a FReep post it usually opens a new browser. Doesn't matter which browser you have, as far as I know. When that happens there IS NO back to go back to in the new browser. You can tell if this has happened by your task bar at the bottom of your screen, which shows you what you have open. I'm just guessing that you have an additional browser open when you encounter this problem. Your other browser is still intact and you can use the back button on that one. It's just a matter of reopening that browser and closing the new one when you are finihsed with it.
Since my problem started today, I'm going to go back to a couple of days ago and see if that fixes it. I don't like what it's doing now.