Editor’s note: Dana Santas, known as the “ Mobility Maker ,” is a certified strength and conditioning specialist and mind-body coach in professional sports, and is the author of the book “Practical Solutions for Back Pain Relief.” CNN  —  If you have ever felt tension in the front of your hips after sitting too long, struggled with lower back pain or had difficulty touching your toes, your hip flexors may be to blame. These often overlooked muscles play a vital role in posture, climbing stairs,