The relationship between these two events is that Shays’s Rebellion helped to bring the Constitutional Convention about.
Shays’s Rebellion was about economic and political grievances on the part of small farmers. Under the Articles of Confederation, the states had all the power and the state governments tended to be very sympathetic to people like those who participated in Shays’s Rebellion. The state governments were very democratic, leading them to have sympathy for the plight of the mass of small farmers.
The economic elites of the new United States were frightened by the rebellion and by the actions of the state governments. They thought the US would end up with mob rule which would take away the rights of the rich. They also feared this would ruin the US economy. For these reasons, they called the Constitutional Convention and created a new, less democratic system with a strong central government.