Alcohol should not cause painful menses or heavy bleeding. It seems that she might be having one of the following clinical ailments:
1. Infection is the most likely possibility. Antibiotics will help her. Since she is sexually active, the chances of Pelvic infection
should be thought first.
2. Tumour in the uterus - mostly fibroid: If it is symptomatic, she will have to undergo removal of tumour.
3. Presence of uterine lining somewhere else outside the uterine cavity
will help to tentatively arrive at some diagnosis.
Please report to the Gynaecologist to get evaluated and treated.