Shays' Rebellion was an armed uprising in Western Massachusetts and Worcester in response to a debt crisis among the citizenry and in opposition to the state government's increased efforts to collect taxes both on individuals and their trades. The fight took place mostly in and around Springfield during 1786 and 1787.
The reason why no–one really knows why he was killed is that there is no agreement about who was behind the murder, who pulled the trigger or triggers, or even how many triggers were pulled. And the reason why there is no agreement about many of the basic facts of the JFK assassination is that the case was never seriously investigated.