I agree with your physician that the soreness in your throat is due acid reflux or heartburn. This is a result of acid form the stomach regurgitating into your throat. Interestingly, when this happens the typical symptoms of burning sensation in the chest is not experienced and yet acid reflux is present. Also this type of reflux is more difficult to treat and requires a higher dose of the medication for a longer period of time. It may take up to 3 months before your symptoms resolve. If you are overweight, it is important you lose weight and avoid spicy foods and not eat at least 2 hours before you go to bed.
You will probably require treatment for about a year after which time the dose of the medication can be decreased and then changed to a less potent medication such as a H2 blocker (ranitidine is an example). If your symptoms recur, you may have to stay on Lanzol indefinitely.