How will I know if I have costochondritis?

Diagnosis of... ...Exclusion. Symptoms of costochondritis are from chest wall pain, which can be hard to distinguish from those of more serious conditions (heart, lung, blood clots). Doctors first "rule out" these other conditions. If your symptoms and the doctors findings while examining you support the diagnosis of costochondritis, there is your answer. Treatment is anti-inflammatory measures & pain relief.
Local pain & tender. Pain and tenderness over the cartilage that connects the ribs to the sternum (breastbone). The pain is usually sharp and made worse with deep breathing and coughing. The pain is usually localized to the area of inflammation. Chest pain from a heart attack is usually behind the sternum, more wide spread and worse with activity but physician evaluation is a good idea for any chest pain.