hi,thanks for query.No,this is not a sign of lymphoma
.the pain that you are having could be due to some gastric discomfort or stimulant effect of alcohol.At times alcohol can lead to this.Rash
under arm pit,could be due to some form of allergy
or skin fungal infection
.Please get your self examined by your doctor and get proper diagnosis done.He may ask for some blood tests like blood counts,blood sugar and other reports as per the need.
wishing you good health.