Inside wear on rear tire. suggestions?

[UberWagen]

I'm a little new to the 318ti suspension. I'm used to VW's, and I've only had the car about a year. Anyway, on to my question. I'm getting pretty bad wear on the inside of my right rear tire. This car is bone stock, and the rear suspension has probably never been touched before. I have a Hanes manual for it, but this write-up for rear suspension is horrible. I see some sites they say the stock rear end is adjustable, or it isn't, or it is, but you need a special tool. That's not helping me fix my tire problem. SO. Am I looking at a ride height issue with a worn spring, a bent arm, worn bushings. OR!? Am I looking at just somehow adjusting the camber a little without having to buy a $400 fully adjustable camber kit. I know you can't give me exactly what it is, all I am looking for is if there are adjustments that can be made, or is something worn out? It's just my rear right, my rear left is fine.