If you have a tight lower back and tight hamstrings, this gentle hip stretch may be able to help.
To do this stretch, lie on your back on a firm but comfortable surface, such as a yoga mat. Bring both your knees up so your shins are parallel to the floor. Gently place your right ankle on the top of your left knee. Grab behind your left knee with both hands to hold your leg in place. You should feel a stretch in the back of your left hip and buttock. If the feeling is too intense, you can release your left leg and rest your left foot on the floor, keeping your right foot resting on your left knee.
Try to relax the rest of your body as you breathe. Hold the stretch on this side to the slow count of 30, then switch sides and repeat.