pain vs break out

pain is a noun but break out is not a noun.

Word	Noun	Adjective	Verb	Adverb
pain	Yes	No	Yes	No
break out	No	No	Yes	No

As verbs, break out is a hyponym of pain; that is, break out is a word with a more specific, narrower meaning than pain:

Other hyponyms of pain include erupt, recrudesce.

pain (noun)	break out (noun)
a somatic sensation of acute discomfort
something or someone that causes trouble; a source of unhappiness
emotional distress; a fundamental feeling that people try to avoid
a symptom of some physical hurt or disorder

pain (verb)	break out (verb)
cause bodily suffering to and make sick or indisposed	become raw or open
cause emotional anguish or make miserable	begin suddenly and sometimes violently
	start abruptly
	take from stowage in preparation for use
	move away or escape suddenly