As the subject of social justice is very large, you will probably have more success researching it if you focus on a narrower topic within it. Below are a few ideas for focusing your research.
Brown v. Board of Education
Same Sex Rights:
LGBT People - Legal Status
Same Sex Marriage
Same Sex Parents
Social justice is defined as "... promoting a just society by challenging injustice and valuing diversity." It exists when "all people share a common humanity and therefore have a right to equitable treatment, support for their human rights, and a fair allocation of community resources." (Toowoomba Catholic Education, 2006).
"The goal of social justice education is full and equal participation of all groups in a society that is mutually shaped to meet their needs. Social justice includes a vision of society that is equitable and all members are physically and psychologically safe and secure." (Adams, Bell and Griffin, 1997)