The relationship between these two events is that Shays's Rebellion led to the calling of the Constitutional Convention.
Shays's Rebellion was a call for the Massachusetts state government to make laws that helped out poor farmers in debt. Many other states had made such laws already. The rich in America at the time were very worried by such laws. They were worried by the fact that states had been passing such laws. This made them want a new system of government in which the states would have less power. Because they wanted a new system like that, they called the Constitutional Convention.