What you are describing is a common complaint among women and has been the subject of a number of research studies. The condition is referred to as post tubal ligation syndrome. Typically, women complain of an increased amount of pain during their periods (dysmenorrhea). The most recent studies have shown no increase in painful periods in those women who had a tubal ligation.
What is found in many women is that prior to the tubal ligation, they were taking birth control pills. After having their tubes tied, the birth control pills are stopped. These women have a return to their “normal” menstrual pattern. While they were on birth control pills, their periods were lighter and not associated with as much pain. This occurs in just about all women who take birth control pills.
As for what you can do now, there is an excellent article on this site about dysmenorrhea, its causes and treatments. This article should provide a nice overview of the subject.