Left psoas pain I interpret as anterior hip pain. This could be your hip joint as well as a nerve referral pain. Obviously, lower back pain is located in a different spot and is normally generated by the lumbar spine. Hyperlordosis doesn’t occur overnight so your earlier X-rays would be helpful to determine your current lordosis which I suspect is within normal limits.
It sounds like flexion (bending forward) relieves your pain. Backpacking causes spine flexion to compensate for a heavy load posterior to your spine. Mountain biking and skiing are also flexion activities. You might have a facet disorder> See:
Donald Corenman, MD, DC is a highly-regarded spine surgeon, considered an expert in the area of neck and back pain. Trained as both a Medical Doctor and Doctor of Chiropractic, Dr. Corenman earned academic appointments as Clinical Assistant Professor and Assistant Professor of Orthopaedic Surgery at the University of Colorado Health Sciences Center, and his research on spine surgery and rehabilitation has resulted in the publication of multiple peer-reviewed articles and two books.