It is common to have lower back pain when standing, especially after sitting for extended periods of time. Working at a desk job for six, eight, or even 10 hours often makes it hard to get up and stretch. Then, when you stand up it is common to have an anterior pelvic tilt, where your hips are more forward, which causes lower back pain due to lack of core muscle core use while sitting. I learned two things to help me relieve this back pain that I experienced from sitting for long periods of time in school and working.
#1 The first one is called a quadricep stretch. You should perform this stretch on both legs. Hold it for 30 seconds, and do it three times. You should feel a stretch in your quadriceps muscles.
#2 The second one is called Tighten Your Glutes Exercise. You can perform this one anywhere, at anytime. All you do is simply squeeze your glutes (butt muscles) to help straighten your posture, and strengthen your core.