Over the years as a massage therapist I have had the opportunity to work on and learn about a muscle called the Psoas Major. When the work is pronounced the p is silent. I have several great pictures here that will show you where the muscle is located.
This muscle can be responsible for a great deal of low back pain. It comes off of the lower lumbar...the bottom 5 vertebrae (T12-L4) then runs through the pelvic bowl, down over the front of the hip joint, and attaches at the top of the femur (thigh bone). It is the only muscle connecting the spine to the leg.
The Psoas is a hip and posture stabilizing muscle and is considered a hip flexor. The Psoas Muscle is responsible for assisting the body in walking, running, riding a bike and any other action that requires bringing our leg up towards our body.
This is a great article about the Psoas and will continue to assist you in learning more about how this muscle works, how to strengthen and stretch it.
The most challenging part about working on the Psoas muscle is that is deep with in us just on the anterior surface of the spine. So it could be considered intrusive and possibly rather invasive to have it worked on....but when it is tight or in spasm....you don't have too many choices.
I like to to resistance with the muscle will stretching. It allows the muscle to release and reduce the pain that is being caused.
Much of the time the muscle is shortened by all the sitting that we now do in front of our computer....lol! I don't know anything about that. So I recommend you get up and move around at least once an hour and if possible do stretches that help give that muscle some much needed lengthening.
My favorite stretch that I share with people is to lay on the edge of your bed and just let your leg drop off of the side and let it hang there. Go to the other side of the bed or turn around and do it on the other side. Do this morning and night!
I've shared this video with clients in the past and have found it to be very helpful in understanding this muscle as well as possibly helping yourself relieve the pain.