Primary dysmenorrhea is the most common kind of dysmenorrhea. Cramps (pain in the lower belly area and/or lower back) can start 1-2 days before your period comes and can last 2-4 days.Secondary dysmenorrhea is when cramps and, for some, lower back pain are a result of a medical problem such as endometriosis or pelvic inflammatory disease.rimary dysmenorrhea is the most common kind of dysmenorrhea. Cramps (pain in the lower belly area and/or lower back) can start 1-2 days before your period comes and can last 2-4 days.