When I take Hatha Yoga, it reminds me how important it is not only to work out but also to lenghten your body. After a long flight my hips are usually screaming at me. Sitting for long hours make your hip flexors shorter and shorter and your lumbar spine compressed so that you don’t feel anymore your natural spine curvature.
One of the suggested pose from the tYoga teacher that you can do is a backbend position like the Supported Bridge, with a bolster under the hips or a block at the level of the sacrum, vertical positioned; if you want to intensify the stretching, try to extend the legs parallel placing your heels against the base of the wall, parallel legs, softening your toes. I honestly hate this last position but after that you are mentally insulting yourself because you’ve put yourself into it in the first place you actually feeling the opening in the front of the hips and consequentially more length in the lumbar spine. Keep it for at least 3 minutes.

(ps: if you have any kind of spine issue/surgery or back pain it’s always better to ask the physical therapy/doctor which kind of exercises are better for you.)

The picture is from the Women’s Health Big Book of Yoga by Kathryn Budig