Lexis Nexis is a great place to start your research when looking for a specific legal case.
Click on the link below and use the center search box labeled Look up a Legal Case and enter the citation or the party names, or a topic if you don't know specific cases.
You can also select "US Legal" > "Federal and State cases" from the left side menu. From this page select Massachusetts from the Jurisdiction drop-down menu and choose either citation or party names from the search menu.
As a shortcut, you can search by case name by simply entering the two party names separated by a "v." (like: Roe v. Wade) and click Search.
To find legal cases and to understand what they mean, it helps to understand how case names and legal citations work.
For a quick introduction go to the center box of this guide from Walsh University.