I had the same problem as you before, but I was very upset. I dare not take off my clothes in front of girls. I also consulted doctors and fitness instructors. According to my own characteristics, my method is to ensure the basic exercise time every day, such as running. Now I spend an hour every day. Cooperate with supine birds (two dumbbells, people lie flat, hands are parallel to the sides of the body, lift up, perpendicular to the body, and repeat), 30 birds in each group, ten groups a day, and persistence for two months will basically achieve satisfactory results, and persistence is the most important.