Gness, before you go ahead and have a shoe built up, might i suggest that you try and chat to as many people as you can that have had this done.
I was in the same position about 15 years ago, I have a curve in my spine and one leg is an inch and a half shorter than the other.
I was told that i had to have my shoe built up, and was told to choose two pairs of shoes, I attended all my hos appointments, and spoke to people in the clinics that had already had theirs done, everyone I spoke to was sorry that they had gone ahead with it.
They all said that they had more pain than they had before the build up.
When I spoke to the doctor, she explained that as my leg had been shorter for quite a while, my spine / hip etc had adjusted themselves to this,
and when the shoe was built up, this would push everything back to how it should be, basically forcing everything back to how it was ten plus years before and could quite possibly be very painful. I talked to a few more people, and decided against it.
I stopped eveything before any shoes were altered and the hospital accepted my decision and were not annoyed. X