Lower back pain can have many different causes. Muscle weakness, poor posture, disc/spinal issues, leg length differential or an old injury can all factor into back pain. That said, this chronic pain can be helped by stretching certain areas and building hip strength.
From a fascial (connective tissue) line perspective, the tension you feel in the lower back could be coming from anywhere along that posterior side of your body. So a tight foot or calf on that side could also be a tight sacrum. Below is a simple foot fascia stretch you could do while watching tv or before a walk/run. If you know you have tight calves, this is my favorite stretch to release the muscles as well as the fascial line.
For a more active approach, anyone with a tight lower back has tight quad muscles (front of thighs). This version integrates a yoga pose with some turbo options for stretching. Your front leg doesn't need to be crossed in front of the opposite thigh, you can just tuck that knee underneath you. You can also place a pillow underneath the glute that is stretching. Just being here may be intense enough. If so, breathe and visualize new space in your hips. You may also feel this more in your butt than in your quad. Try to bend the elongated leg for the thigh stretch. If your hamstring cramps, scroll up and do the calf stretch first. If you can bend the knee, this stretch is a great twofer for the thigh and rear.
Another area that can pull on the lower back is the groin. Most of us never think to stretch here yet it can really compound tension in the lumbar spine. This is a pretty intense stretch, so here is a more gentle stretch.
When you're out of the pain or as a preventative measure, you want to build hip strength. If you've recently had pain, doing this may not feel good, so listen to your body. If you feel a sharp pain, this is not for you right now. You may need more individualized help, so gimme a call! Or, reach out to your trusted chiropractor, massage therapist or physical therapist.
I find that lower back pain perhaps more than any other chronic pain area always has an emotional or stress-holding connection. I already wrote about how lower back pain connects with breath holding here. Some things to explore for the emotional connection would be: When did this pain start? What else was going on in your life around that time? Does the pain tend to get worse during certain times of the day? If it's in the morning, are you happy in your work/relationship? In the evening, are you feeling burdened by your responsibilities? Does it hurt more when you speak to a certain person? Are you holding or internalizing anger, frustration or another emotion with regard to that person?
Noticing your personal patterns can help you start to process some of these underlying aspects that are keeping this pain chronic. I believe this is a big reason why a massage or even a stretching routine doesn't keep the pain from coming back. If some of this resonates for you, visualize these emotions/memories leaving your body via your breath. Let it go!