Hi and Thank You. The static came from just about everything I touched in he store. From a jar of pickles to the freezer doors and the worst being a can of tuna. Before I even got my hand on the can it felt like the static jumped out at me into my hand. When this happened it let out the loudest pop of all. It literally hurt like heck and was really scary. I've shopped in this store for over 15 years and nothing like this has ever happened. I was told it was caused by them waxing the floors and not buffing them out yet to it being the new carts. This was affecting a lot of people in the one hour I was in the store that day. It just seemed to be affecting me more. That's why I was curious about the steel rod in my back and if that was why I was getting shocked worse. Thanks!
What it seems to me you are in effect asking is whether having a steel rod in your body would increase its capacitance significantly. Because that's what I think would be required for you to experience a uniquely strong electrical discharge. The voltage you pick up will be determined whatever is casing the charge separation to take place, i.e. your shoes and the floor, so a stronger discharge must imply that somehow you are storing more coulombs of electricity, at a given voltage, than someone else, i.e. your capacitance is higher.
I suppose that the presence of an internal, polarisable conductor might increase it to some extent, but normally static charge sits on the outside of objects, so perhaps not much. It's an interesting question. Perhaps you should offer yourself to a local uni physics lab to test it. I'm sure they could measure it as a project for the students - if you can stand a few mild shocks.