torso["Right Shoulder"].C0 = torso["Right Shoulder"].C0 * CFrame.new() -- Like this
torso["Right Shoulder"].C0 = torso["Right Shoulder"].C0 * CFrame.Angles() -- Like this
torso["Right Shoulder"].C0 = torso["Right Shoulder"].C0:Lerp() -- Also this
The problem with your code is that you can’t assign a Vector3 value to the rotation and position properties of CFrame. Rotation and position need to be assigned to a CFrame value. To fix this, you can use the CFrame.fromEulerAnglesXYZ() function to convert your Vector3 values into a CFrame value. The code should look something like this:
local tool = script.Parent.Parent
local Character = plr.Character or plr.CharacterAdded:Wait()
local torso = Character.Torso
tool.Equipped:Connect(function()
torso["Right Shoulder"].C0 = CFrame.fromEulerAnglesXYZ(1, 95, 90)
torso["Right Shoulder"].C0.Position = Vector3.new(1, 2, 8)
end)