Hi Susie
Sorry to hear about your gallstones, Sounds really painful

I haven't done any research so could be wrong here but I've never heard of asthma drugs causing gall bladder problems. I had always thought gallstones were mainly made up of cholesterol & were caused by a person's diet.
Don't know if it's just a saying in the UK but they always used to say that the prime candidates for gall stones were 'Female, Fair, Fat & Forty.' I think it's more common in woman than men so my guess is that it wasn't caused by your asthma drugs, it was probably going to happen anyway. Best to ask that doctor you're going to see.
Since I hit 40 I've had all sorts of problems ranging from cancer to carpal tunnel syndrome & lots of other stuff in between. I've stopped looking for the reasons & put it down to getting older.

Hope you get the problem sorted out & are back to good health soon.
Lidia