The labor laws require an employer to pay its employees for all hours worked. This includes any work done before the start of a shift, and after the end of a shift. If your employer requires you to show up 15 minutes before your shift to prepare, that time should be paid. If you have a blackberry or a smart phone and you are required to answer work email when you're out of the office, you should be paid for your time.
Does your employer make you change into a uniform at work, before you punch in? Do you have to punch out at the end of the shift before you change out of your uniform? If so, you may have been denied pay that you're entitled to under the law. This is known as a "donning and doffing" claim.
If your employer requires you to do work when you are "off the clock," contact us to discuss your options.