Can drinking alcohol irritate gall stones?

Absolutely: Alcohol is a well known risk factor for liver disease and particularly pancreatitis. The gallbladder, particularly, sick one reacts unpredictably to alcohol ingestion and may very well trigger a biliary colic and worse case scenario, pancreatitis, which can be fatal.

Yes and no: Alcohol itself is not a common exacerbator of symptomatic gallstones. More commonly fatty meal which stimulate gallbladder contractions can increase symptoms. Excessive alcohol consumption such as binge drinking can cause hepatitis and liver pain which can mimic gallbladder disease.