Underbody Shield problems of the 1998 Chevrolet Blazer

Vehicle pulls to the right with violent vibration when going over 45 mph. Have replaced the ball joints, new tires and had vehicle aligned 2 times. Two shops stated that there was nothing more they could do. Both found that the wheel base was off. The right side of my vehicle is 1/4" shorter than the left. Had vehicle inspected to see if it had been wrecked. Two body shops stated that there was no visual signs of a wreck. The carfax report came back that there had been no wrecks. Body shops also stated that putting the vehicle on a frame puller would not help because after taking it off the frame would most likely go back to the way it was. Went ahead and tried and the were both right. Have spent too much money trying to fix this problem and am in the process of speaking with Chevrolet headquarters. Any idea on what to do? thinking of contacting my lawyer.