growing pains vs pain

growing pains and pain both are nouns.

Word	Noun	Adjective	Verb	Adverb
growing pains	Yes	No	No	No
pain	Yes	No	Yes	No

As nouns, pain is a hypernym of growing pains; that is, pain is a word with a broader meaning than growing pains:

Other hypernyms of growing pains include painfulness.

As nouns, pain is a hypernym of growing pains; that is, pain is a word with a broader meaning than growing pains:

growing pains: pain in muscles or joints sometimes experienced by children and often attributed to rapid growth
pain: a symptom of some physical hurt or disorder

Other hypernyms of growing pains include hurting.

growing pains (noun)	pain (noun)
problems that arise in enlarging an enterprise (especially in the early stages)	a somatic sensation of acute discomfort
emotional distress arising during adolescence	something or someone that causes trouble; a source of unhappiness
pain in muscles or joints sometimes experienced by children and often attributed to rapid growth	emotional distress; a fundamental feeling that people try to avoid
	a symptom of some physical hurt or disorder

growing pains (verb)	pain (verb)
	cause bodily suffering to and make sick or indisposed
	cause emotional anguish or make miserable