Phrenodynia, also known as diaphragmatic neuralgia, refers to pain in the diaphragm, which can arise from irritation of the phrenic nerve. This condition may manifest as sharp or stabbing pain in the chest or shoulder area, often exacerbated by breathing or movement. It can be caused by various factors, including trauma, inflammation, or underlying medical conditions. Treatment typically involves addressing the underlying cause and may include pain management strategies.