Got to know I have gallstones thinking the pain was due to acidity

So since many years I used to think I have acidity issue. And since last 6 7 months I used to have this stabbing pain on my upper abdomen which escalated to back pain. I used to have this unbearable pain once or twice a month. I always considered it as acidity issues. Now that I have got it checked and through ultrasound I got to know that I have some 9mm stones.