Thanks for posting your query.
Upper gastrointestinal tract symptoms are least correlated with left sided neck and shoulder.
Although gall bladder
symptoms may be related with right sided shoulder & neck pain
but pain on left side is least likely.
Ingestion of rum may cause damage in esophagus
, stomach and liver and involvement of all these organs are not related with left sided neck & shoulder pain
You should consult with internal medicine specialist and should go for ECG as a preliminary test.
Involvement of heart may cause left sided neck & shoulder pain.
In case of any doubt, then you should go for coronary angiography
Dr. Mayank Bhargava