If you can manage your pain, and if you can do your job without causing more pain, it's probably OK to work. If your pain is severe, and if your job makes it worse, then you may need to a short time off. 

When your lower back pain interferes with your job, you need to see a doctor. Your doctor will be able to help you manage your pain. Your doctor can also give you guidelines on how to do your job so that you don't further injure your back. Your doctor may also put limits on the amount of time you should spend sitting, standing, or walking, and may restrict you from tasks such as lifting or carrying heavy items. You may also need to work with a physical therapist to help you control your pain and strengthen your back. The key is to get you back to your normal activities as early as possible, including work.