Pains \Pains\, n. Labor; toilsome effort; care or trouble taken; -- plural in form, but used with a singular or plural verb, commonly the former.

And all my pains is sorted to no proof. --Shak.

The pains they had taken was very great. --Clarendon.

The labored earth your pains have sowed and tilled. --Dryden.

Source: Webster's Revised Unabridged Dictionary (1913)