I presume you're saying that her only reason for visiting the ER was to
obtain relief from the pain (no other complicating factors)?

The pain of kidney stones is among the most intense there is, and so it
demands extremely powerful painkillers, most of which are controlled
substances.  I suppose that's the reason for the ER visits.  How is the
painkiller administered?  If it's an injection, I can see why it might
be difficult to obtain in any other way--thanks to the War on Drugs,
most people would equate home parenteral administration of controlled
painkillers with drug addiction, even though the connection between
proper analgesic use of narcotic painkillers and addiction is very weak.

My wife has seen numerous doctors for kidney stones and finally seems
to have stopped forming them by changing her diet, eating better,
drinking a lot, etc.  However, in passing the ones she still has, they
all seem to end up with 1-2 trips to the ER.  Is there any alternative
to controlling the pain, then going to the ER?  We've been to the ER 6
times in 3 weeks.