I think, therefore I suffer.
I believe Doleo would be the verb (doleo dolere), the word for pain ie a pain (noun) is dolor, doloris (masc)
A Latin equivalent of the English adjective 'smart' is acer, acerbus, or gravis. Each of the Latin adjectives means 'smart' in the sense of 'painful'. Another Latin equivalent is lautus, mundus, nitidus, or ornatus. Each of the Latin adjectives means 'smart' in the sense of 'fine, elegant'. Still another Latin equivalent is salsus, which means 'smart' in the sense of 'witty'. The Latin equivalent of the English verb 'to smart' is doleo, dolere. The verb means 'to smart' in the sense of 'to suffer pain'. From it derives the English adjective 'dolorous'.
I believe Doleo would be the verb (doleo dolere), the word for pain ie a pain (noun) is dolor, doloris (masc)