I''m in a similar position, not with Gall sotnes but Kidney stone(s). Back in 1993 I had a VERY painful experience with a kidney stone that tried to work it's way out, got stuck, and blocked the tube out of my kidney. I cannot begin to describe the pain, which lasted 3 days, and was treated with morphine injections (wow !).
Just had my class 2 medical, and as it's on my notes as an occurence worthy of note, I have to have ultrasounds and X-rays tomorrow, to see if there are any there. If not, fine, but if there are I have to have them broken up, and remain stone free. Until that time, I can't do my 1st solo (which I was ready for after 7 hours of instruction), and can only fly with my instructor. So, my PPL (A) is held up now, because of an insident that took place 13 years ago !
I can however see the CAA's logic on this one, as if I did have an attack, in flight, the last thing on my mind would be a nice safe landing. Sounds similar to gall stones in that respect in that the pain is quick to come on, and completely debilitating.
Fingers crossed for my scans tomorrow !