My lg secret turns off

You could have possible liquid or shock damage done to your phone. If it has been dropped multiple times it could be suffereing from shock. It doesnt matter where you are or the time of day those issues are sort of sporadic and unpredictable. If the phone has liquid damage (sweat, moisture, steam, juice, oil, saliva, etc.), the motherboard could have been short circuited which leads to power cycling of your device. There should be a lithmus paper on your battery and your phone that should be white or white with purple or red x's on it. If the paper is red, pink, or purple you may have possible liquid damage. You may need to also test your battery to ensure it is not shorted or has a low SOC.