Welcome to the forum from Oregon.
How about sharing the year, make and model.
Since you do not have rear independent suspension I can only assume you may have hit something and bent to where the wear is being caused. You may also have a bad bearing or bent axle hub but since the axle hub spins, you should feel a wobble at the same time. You need to get the rig on an alignment rack and get a printout of the OE specs and what the readings are at this time. It could be a tire problem and not the suspension. Is this a tire that recently was rotated to the rear? Maybe problem is at the front if that is the case.