Melectrok

When I lay under my car and look at the driveshaft maybe 6 inches from the transmission. It isnt centered. If you compare it to the pads that your seatbelts bolt to, on the pass side there is like one inch, where on the drivers there is about 2. Is this anything to worry about? If its a problem, what would be a common cause. I can push up and down on the driveshaft about + or - 1 inch. But cant get any side to side movement.