1996 Nissan Maxima how to straightin a rear tire

Are you asking how to fix a bent rim/wheel or how to check for bent rear suspension?

If it is bent rim, check your local yellow pages for a shop that repairs bent wheel.

If you need to check the suspension, raise the rear of the vehicle, remove both wheels, and measure the distance between parts on the left side, and cross-check the numbers with the measurement on the right side. I have a feeling that you bent the torsion bar.