Costochondritis is caused by inflammation of the cartilage between the ribs and the breastbone, called the costosternal joints. This uncommon condition can trigger a stabbing, aching pain that's often mistaken for a heart attack. Very often, the etiology is not known, but it can result from trauma, eg physical strain, lifting heavy weights or strenuous activity, and arthritis. Even severe coughing can cause costochrondritis.
The main symptom of costochrondritis is chest pain, which may be sharp or dull ache. It tends to be aggravated by deep breathing or coughing, and pressing on the rib or chest can make you feel tender and even swollen. However, people having heart attack often say they feel chest discomfort rather than chest tenderness. They describe it as feeling squeezed, chest tightness, or even pressure. If you have sudden chest pain, it is still always ideal to have it checked out by a doctor to make sure your heart is healthy.