What Causes Excessive Bleeding With Pains During Menstruation?

Hi, may I answer your health queries right now ? Please type your query here...thanks my doctor.I am a man of 28 yrs old dating a fiancee age is 26 with a height of 1:65;(,she is experiencing pains at her menstruation which bleeding that flows out is much more than normal and lasted for 5 days instead of 4days,what is happening and what could be the solutions.thanks.