hi, thank you for providing The brief history of you. A thorough clinical examination is advised. As you get pain while bending and activity than you should take an x-ray of chest to check costochondritis and also ultrasound scanning of the abdomen to rule out pathology of the organs of abdomen in the upper quadrants. Post diagnosis the treatment will be planned and guided. Also doing costal breathing exercises, diaphragmatic breathing exercises, abdominal breathing exercises should help strengthen the muscles. Brace has got limitation and should be avoided for longer run as it may lead to muscle weakness more. Regards Jay Indravadan Patel