Thanks for all the great feedback!
I have a portable Honda inverter generator that is supposed to shut down and indicate any shorts or ground leaks, so I plugged the motorhome into that generator to see what it says, and found that there was no problem or shocks when plugged into the portable.
I then ran the cord inside the house and plugged it into the laundry room plug (not the 220v, of course). No problem, everything worked great & no shocks.
Happily, I guess the problem was in the garage plug. This is the same plug I have always used, so I don't understand why this just started. I turned off the garage breaker on the house & I'll call an electrictian when I we get back from our trip.
Thanks again for all the help. I love this forum! (and it has saved me lots of $$$$$$)