Girls’ shoulders become thicker, the common reasons are mainly the following: 1, adolescence, girls due to faster growth and development of the body, can cause the bones and muscles at the shoulder significantly increased, manifested as shoulder thickening, is a normal physiological phenomenon, no need to worry too much; 2, during pregnancy due to eating a lot of high sugar, high protein, high-fat food, can cause the body fatty tissue accumulation in the shoulders, back, the abdomen and other places, causing thickening of shoulders and weight gain. The symptoms of shoulder thickening can be reduced by improving the diet structure, eating more vegetables and fruits, and reducing the intake of greasy food; 3. When doing fitness exercise, due to inappropriate exercise methods, it can cause the shoulder and back muscles to thicken significantly and the shoulders to become wider. It is recommended to carry out gradual fitness exercise under the guidance of a professional fitness instructor to avoid gradual thickening of the back of the shoulder.