It is only recently that I have started to learn and accept what I now think is the true meaning of this verse. You see this pain and illness does not feel good and I don't think it is good, but that does not mean that God is not working for my ultimate good. I have been learning more and more that I do not always know what is best for myself. I often think I know what's best for me and yes it may be the thing that feels better and easier in the short term, but long term I don't have a clue.
It is an incredibly hard thing to accept, that God ultimately knows what is good for me and I don't. It is an incredibly humbling place to be, and to get there a lot of pride had to be knocked down (and is still in the process of being knocked down.) God has eternal plans, eternal timings... I am lucky if my plans are for more than a week ahead.
Slowly, very slowly I am learning that God does work for my good. That doesn't mean He works in the way I most want Him to; it does not mean He works in the way that is easiest for me, but He is working for my good.
Now it is still hard to read that verse, it is still hard to see that this pain could be good, but instead of reading it with anger, I can now read it with acceptance, excitement and anxiousness of what good God is going to bring out of the situations He places me in.