What if I am in a metal cube touching the surface of the cube and lightning strikes the cube. Will I get shocked?
I think this is an experiment that you should not be trying.
The National Lightning Safety Institute have issued the following statement:
Reported incidents and related injuries make it clear that a person inside a fully enclosed metal vehicle must not be touching metallic objects referenced to the outside of the car. Door and window handles, radio dials, CB microphones, gear shifts, steering wheels, and other inside-to-outside metal objects should be left alone during close-in lightning events. We suggest pulling off to the side of the road in a safe manner, turning on the emergency blinkers, turning off the engine, putting one's hands in one's lap, and waiting out the storm.
So although perhaps in theory you can touch the inside of a metal cube and survive when it is struck by lightning, in practice it is advisable not to do so noting the "putting one's hands in one's lap" advice.
we know that any charges on the conductor lies on its outer surface(gauss law) therefore any induced charges would never make it to internal surface, hence you wouldnt get shock before lightning strucks.
Now during lightning strikes if the cube is perfect conductor then all charge would flow through cube only but in reality the cube would have some resistance and we can consider our body to be another resistance connected in parallel so we will get a shock
I think you'll get a shock. Based on elementary electrostatics let me try to reason it. I might be wrong so please correct me in case of inconsistency.
How does lightning work?
First clouds gather some amount of charge and induce that charge on objects on earth. Assuming that there's nothing nearby except your metal box, the surface of your metal box will acquire a positive charge. When there's enough energy to break air's resistance the current will flow from clouds to your box neutralizing it.
Will you get a shock?
If you touch it just before the lightning strikes (when the metal is charged).. you should get a shock. If you're alive(not cooked!) after the lightning struck then you should not get a shock.