According to the American Chiropractic Association (ACA), lower back pain is the second most common reason for visiting the doctor. It's also one of the most common reasons for calling out of work. What are the causes of lower back pain? According to the ACA, one of the causes of lower back is poor posture and if your job requires you to sit at your desk all day, then this can become the cause of poor posture and lower back pain. We've put together 4 yoga poses that can alleviate lower back pain and help improve your posture.