Hip Flexor Stretch
The hip flexor muscles are a huge contributor to low back pain. This muscle group attaches on the front of your leg as well as on your spine in the back! When these fibers are too tight from activities like sitting in your car, sitting at work (sounds like your daily schedule), or your horrible ab routine for those that hit the gym, your lower back gets compromised and put in a position of lordosis (larger curve than you should have). Once in this state of lordosis, your vertebrae are in a position where joints can hit each other and cause pain! Not to mention they wont be able to safely handle the same loading forces of a normally curved spine.
If your day consists of sitting and/or you really don't know what your doing in the gym to target your abs, this stretch is a must!!
Start in a lunge like position with your back knee on the ground, keeping your back straight and your core engaged, push your hips forward until you feel a stretch on the front side of your hip/leg, Hold this for 30 seconds. Apply this same stretch to the other side.