Muscle after injury or strain, manifested as a hard mass inside, can be seen in the following cases: First, local muscle fiber rupture or tendon injury, there will be a local contraction of the muscle, manifested as a local mass or hard mass, early should further choose surgical treatment for local repair or anastomosis, if longer, it is easy to lead to adhesions, increasing the difficulty of surgical treatment. Secondly, there are some patients who form mechanized inflammatory masses due to hematoma, which also present with pain as well as discomfort symptoms. The surface of the mass is smooth and the boundary is clear, and there can be mild tenderness. You can apply heat to the mass, which can make the hard mass gradually subside, and if necessary, you can choose the surgical method to remove the inflammatory mass under local anesthesia, and pay attention to regular drug changes after surgery to avoid the occurrence of infection.