A little pain in the right upper chest when taking a deep breath may be caused by chest muscle strain, herpes zoster, pleurisy and so on. 1. Chest muscle strain: the disease refers to the muscle in a rapid and strong contraction or overstretching state, will exceed the capacity of the muscle tissue and lead to muscle tear or rupture, the clinical manifestations of the sick people have muscle pain, skin bruises or swelling. If the chest muscles are strained, deep breathing makes the injured muscles move and aggravates the pain symptoms. 2. Herpes zoster: an infectious disease that affects the skin and nerves, caused by the body infected with varicella zoster virus, the clinical manifestations of blisters or papules in the chest, abdomen and other parts of the chest, accompanied by significant persistent pain, skin exudate and other symptoms. The skin of the chest will be pulled when the sick people breathe deeply and aggravate the pain symptoms. 3. Pleurisy: the inflammatory reaction caused by various pathogenic bacteria invading the pleura, with clinical manifestations such as chest pain, accompanied by dyspnea in severe cases. In addition, pneumothorax can also cause pain in the right upper chest when taking a deep breath. If the pain persists, it is a sign that the disease has not disappeared, and it is recommended to go to the hospital for examination and targeted treatment.