Breathing or coughing are all caused by strenuous exercise and inhaling too much cold air! Thoracic vertebra disorder, compressing nerves! During strenuous exercise, the muscles secrete too much lactic acid and the muscles can't relax, which leads to muscle tension and pain (massage or wait for a few days). Exercise is not enough for one or two strenuous exercises! Need to persevere! Be sure to warm up before exercise and relax after exercise!