A shrug of the left side of the chest tearing pain may be the adverse symptoms caused by pneumothorax, may also be local muscle strain, intercostal neuritis and other causes of adverse symptoms. 1. Pneumothorax: pneumothorax may lead to a shrug of the left side of the chest inside the tearing pain, the upper limbs after strenuous activities, the pain will be more obvious, the patient may also have a dry cough, poor breathing and other adverse symptoms. 2. Muscle strain: muscle strain in the left chest, may also cause a shrug of the shoulder tearing pain symptoms, usually local muscle strain or injury caused by discomfort, regular lifting and pulling heavy objects or overexertion may occur, accompanied by a feeling of soreness and swelling. 3. Intercostal neuritis: a shrug of the left side of the chest inside the tearing pain, may also be intercostal neuritis caused by the discomfort, shrug of the shoulders may make the affected area is pulled, the pain symptoms will be more pronounced, some patients will also have a burning sensation. There are many reasons for such symptoms, it is recommended to go to the hospital in time for a comprehensive examination, according to the doctor’s advice, choose the appropriate treatment.