MouseState previousMouseState;
    protected override void Initialize()
    {
        // TODO: Add your initialization logic here
        //store the current state of the mouse
        previousMouseState = Mouse.GetState();
    }


    protected override void Update(GameTime gameTime)
    {
        // .. other update code


        //is there a mouse click?
        //A mouse click occurs if the goes from a released state
        //in the previous frame  to a pressed state
        //in the current frame
        if (previousMouseState.LeftButton == ButtonState.Released
            && Mouse.GetState().LeftButton == ButtonState.Pressed)
        {
            //do your mouse click response...

        }

        //save the current mouse state for the next frame
        // the current
        previousMouseState = Mouse.GetState();

        base.Update(gameTime);
    }

//Create this variable
MouseState mouseState;

mouseState = Mouse.GetState();

if (mouse.RightButton == ButtonState.Pressed)
{
     //Do Stuff
}