The doctor is wrong.Those are stones.He does not want to admit that because they do not like if someone not a doctor can remove them with no surgery.They would be happy if you would have a surgery and if your insurance could pay 20.000$ or so for it.Remember that is a bussiness like many others.
My grandfather was a bucher and he told me that pigs get a lot liver stones .They are similar to humans.We live much longer than pigs and we get much more stones during the life.Also our diet is much worse than pigs diet.
So do not trust your doctor.Do what is good for you.