I have noticed that recently when I drink alcohol (once a month-ish) I have an aching pain in my in my shoulder about 20 minutes after my 1st drink.

More history. One would need more history to better assess the possibilities of what might be going on. There is a syndrome of hepatitis with referred pain to the shoulder and chest; however, without further understanding of the situation, it would be difficult to ascribe this to your situation. Best to be evaluated by your local health care provider who can delve further into the details.