It's good that they're being thorough with your care. Better to catch things before they become a problem, especially during or after surgery.

You might not need surgery for you gallbladder, they may be able to remove the gall stone. You'll get a general anesthetic for the procedure but it's a fast procedure that only takes 15 min or so. When I had it done I was able to walk afterwards.

You're in good hands, bf.