Boy! What an episode! How scared you must have been!

I sure can't think of any particular cause of what you are describing.
Was your unit turned on when this happened.....and is the unit on now as you describe this pain moving down your ribcage? If so, perhaps the placement and/or settings of the electrodes are such that the stimulation is reaching around the front - like a 'grabbing' sensation.
I remember when I was initially getting my settings, the Rep asked me if the stimulation was reaching my lower extremities and I said 'yes'.....and as she continued turning up the amplitude, I said that it was starting to stimulate 'too much', as in - around my waist and that's when she said 'ok, then we don't want to go that far'.......

Does the pain stop when you turn the unit off?
If not, then perhaps it is possible that your dura was punctured and nerves were injured (as you have said)....... do you have a severe headache, as would be evident with a CSF leak?

I'm just throwing some thoughts out there......?.....
I guess the main thing is knowing if this pain is happening when your unit is on or off? If your SCS is on, then it would probably be something to do with the settings......
If you are in this pain and the unit is off, then it could be any number of things........of which they probably rattle off as they read you the 'small print' of the risks involved with this....(or any) surgery procedure.....

I wish you the best.....
Please keep us informed of what your medical team is doing about this....

Truly Caring
Rae