backs of some fridges do freeze evenly as it is how they work BUT if you are getting a large ice formation on one side then you have an issue.could be air getting in or a gassing/system issue which to be honest makes it scrap due to repair cost.If there is a drain channel at the back and that freezes up you need to unblock it.Generalising due to a lack of make and model info posted by yourself
CK, October 2013
Does the thermostat seem to be making any difference? Could be that the thermostat has gone and the fridge is pushing to get as cold as possible regardless of the setting. Cheap fridge thermometer from ebay should help you to test.
