I don't know if you are a man or a woman. If you are a woman, you can simply spread a blanket at home or lie on the bed, spread your arms to both sides, have a T-shaped body, put your big arms on the ground, bend your big and small arms 90 degrees, and tighten your chest muscles. Just hold this position for about 30 seconds and breathe gently. 10 seconds later, one group relaxes, and four groups are one group. If you are a male, I feel that all the exercises that stretch the shoulder and back muscles should be helpful, such as dumbbell side lifting, or equipment that directly stretches the chest muscles.