Sigh is a type of Breath. the first thing you do when you Born is Breath. 
Lung is etymologically related to Light. Light is related to Sun. Sun is related to Burn. Burn is related to Painful. 
Sigh --IsA--> Breath <--HasFirstSubevent-- Born 
Lung --EtymologicallyRelatedTo--> Light <--RelatedTo--> Sun <--RelatedTo--> Burn <--RelatedTo--> Painful 