If you are suffering from lower back pain from standing on your feet all day, then try the 'Diaphragmatic Breathing'. Weak abdominal muscles are often the cause of lower back pain which can be helped by doing some diaphragmatic breathing.
This is achieved by breathing through your nose and out through your mouth, allowing the mouth to stay open in a relaxed way. Concentrate on breathing in deeply so you feel your abdomen rising as you breath in. Your chest should hardly rise. Next, breathe out, keeping your jaw relaxed and allowing your abdomen to sink. Repeat a few times.
Diaphragmatic breathing is intended to help you use the diaphragm correctly while breathing to
Strengthen the diaphragm
Decrease the work of breathing by slowing your breathing rate
Decrease oxygen demand
Use less effort and energy to breathe
This website shows you how to go about achieving this technique http://www.cchs.net/health/health-info/docs/2400/2409.asp?index=9445