Sometimes a hernia is noticed after a strain - for example, after lifting a heavy object. Sometimes one may develop for no good reason and you may simply notice a small lump, usually in the groin area. Usually, at first, the lump can be pushed back but may pop out after straining again. Coughing is a common strain that brings them out. The swelling often disappears when you lie down.
This is a companion discussion topic for the original article at https://patient.info/digestive-health/hernia-leaflet