In general, grievance (from class. lat. gravis: heavy) is a wrong or hardship suffered, real or supposed, which forms legitimate grounds of complaint. In the past, the word meant oppressive state of things.
History and politics
The revolt of English barons in the early thirteenth century which led to the Magna Carta of 1215 was partly motivated by grievances against abuses by King John. This right to Petition the king, for grievances, was affirmed in the Bill of Rights 1689
The United States Declaration of Independence is mainly an enumeration of the colonists' grievances against King George III.
References
Grievance Wikipedia(Text) CC BY-SA