Good that u have uploaded Ur whole back picture. As your pelvis is tilted forward so ur lower back is with increased arch. To compensate your lower back arch, your upper back(thoracic spine) has increased roundedness which is leading to rounded shoulders.
Ur treatment will involve abdominal muscles strengthening, lower back muscles stretching, upper back muscles strengthening and chest muscles stretching exercises. We call it cross syndrome.
Next Steps
U should consult online for proper guidance for exercise prescription and posture correction.