Hello Now diagnosis is established , so you can concentrate solely on this point. Gall stone is usually multiple but in your case it is one 8 mm size , very small . I want to tell you that gall bladder stone is very common , exact reason is not known. Now a days for dissolution of cholesterol-rich-gallstone is used URSODEOXYCHOLIC ACID orally . Dosage :6-12 mg daily as a single dose at bed time or in the 2-3 divided doses contined for 3-4 months after radiological disappearance of stones. Doses may be divided unequally w/a higher dose given before bed time to counteract increase in biliary cholesterol situation which occurs in early morning . Maximum doses 15 mg /kg. This is a commonly used drugs for gallbladder stone , so you can try . Mild side effects are there but benefits are more , so you can use . Nausea , diarrhea , pruritus , gall stone precipitation are common side effects. Hope this will help you. Other option is surgical removal of gallbladder . But in my opinion take this treatment regularly and also get in ultrasound after every one month to observe the size of gall stone , even size increases after 3 months treatment then get a surgery. Hope this will help you.