Your QL, or quadratus lumborum can be a huge player when it comes to lower back pain. If you sleep on one side, sit on a wallet or if you tend to lean to to one side when standing...this can all cause your QL to tighten up.
Here's a simple stretch to help alleviate the tension you may feel in your QL. Try holding each side for 10-20 seconds for 3 reps. And remember to breathe! You will notice the more you breathe the deeper the stretch can become. Share this with someone who you think this might help!