When discipline is based heavily on enforcement, complaints will inevitably arise from too rigid adherence to rules or from excessive penalties for violations. But discipline related problems are not the most frequent sources of grievances. Dissatisfaction leading to grievances can come from almost anywhere. Complaints about discrimination and favoritism in work assignments, work standards, or physical working conditions are frequent sources of grievances. It is important to remember, though, that anything about which an employee is dissatisfied can lead to a serious grievance. Grievances need not necessarily be based on real problems; they can be the result of misunderstandings.
When grievances gets deep that leads to conflict, like, conflict within the work organization between the union leaders and managers, between the union leaders and workers and between the work organization and union organization. There are various reasons of conflict. Like economic causes, political causes, social causes, technological causes, psychological causes, market situation and legal causes.
Grievances and conflict are related to each other, one leads to another. So to deal with the grievances and conflict, we need to follow the grievance procedure.