Towing Issues: rear wheel end trouble, laser alignment, man hole

Question
i had my Monte Carlo towed on a flat bed to the repair shop for a water pump hose . when i picked up my car and was going down the road that has the man hole covers my back end of the vehicle felt weird ,  i then rode over another one and the back wheels felt as if they went sideways . i took it back and they couldn't find anything wrong with it when they drove it , so i dealt with it about another week and took it back for them to ride with me . this time he felt it , it felt like he said , that the wheels throw the vehicle in the opposite direction , he looked at it again and said maybe i need a 4 wheel laser alignment . my front wheels go perfectly straight and i was told a long time ago that with rear wheel drive you don't need an alignment when you get new tires so ? do you think like someone told me that my car was chained and they probably hit a big bump and it messed up my car . I'm so upset because my car didn't do this before it was towed . i just got new tires and had all my tires balanced 2 weeks before this . please let me know what you think. thank you very much .sincerely donna  

Answer
What year Monte Carlo? It is possible that when the vehicle was towed that the driver got one of the tie down chains or hooks on a part of the rear suspension and bent it. This would cause the issue you are describing. I also have a Monte Carlo and the same thing happened to it before I purchased it.