:: an unpleasant physical feeling caused by an illness or injury
chest/stomach pains
Are you in pain? (be in pain — адчуваць боль)

:: sadness or mental suffering caused by an unpleasant event
I can't describe the pain I suffered when he died.

be a pain (in the neck) — to be annoying (informal)
My brother can be a real pain in the neck sometimes. (нязносным, нясцерпным)

be at pains to do sth (take pains to do sth) — to make a lot of effort to do something (намагацца штосілы, з усіх сіл старацца зрабіць што-н.)
He was at great pains to explain the reasons for his decision.

on pain of (under pain of) — пад пагрозай, пад страхам чаго-н.
made to leave the country on pain of death

боль