So i have been working at UPS for about three months in the Preload (Ive been unloading almost the entire time except for 3 days where i loaded the trucks) and im thinking about quitting. I feel like i am destroying my shoulder and my back has been giving me an insane amount of pain. and im only 21 so i really dont feel like crippling myself to young. Would i call my supervisor to tell him im quitting or someone else? also would it be bad to not give my two weeks notice? I really enjoyed my job, it just caused me alot of pain, so i would like to leave on a good note.