Some people have to work and stand for long hours at a time. If you must do this, then make sure you try and stand tall and straight. Try and allow your legs to rest too from time to time if possible, perhaps on a stool or bench if you are allowed to do that.
Begin with the basics when treating your back pain. Even resting your back for a couple of days can help ease pain. As you wait for your body to feel better, consider taking ibuprofen, acetaminophen or another anti-inflammatory pill so that you can get more comfortable. Additionally, try alternating cold and hot treatments to stimulate blood circulation and loosen back muscles.