ail vs pain

ail and pain both are nouns.

Word	Noun	Adjective	Verb	Adverb
ail	Yes	No	Yes	No
pain	Yes	No	Yes	No

As verbs, ail and pain are synonyms defined as:

Other synonyms of ail include trouble.

ail (noun)	pain (noun)
aromatic bulb used as seasoning	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

ail (verb)	pain (verb)
be ill or unwell	cause bodily suffering to and make sick or indisposed
cause bodily suffering to and make sick or indisposed	cause emotional anguish or make miserable