birth control pills and painful cramps?

Firstly, hormonal birth control will NOT help with painful periods and irregularity - the pill works by suppressing your menstrual cycles in order to prevent ovulation, as you no longer ovulate you no longer menstruate - the bleeding women experience on the pill is a withdrawal bleed controlled by the order in which they take their inactive pills. Withdrawal bleeds occur regularly and may not be as painful as menstruation, but it's not the same as regulating menstruation or treating painful periods - these symptoms were caused by an underlying health problem, while on the pill that problem is left untreated.

Hormonal birth control can cause a wide range of side-effects, after all it suppresses over 150 different functions within your body, and that even includes IBS - it may just be that your body needs time to adjust, we normally recommend staying on the prescribed brand for 3 months to see if it works for you before you consider switching to something else. If it's intolerable, gets worse, or doesn't ease after 3 months talk to your doctor about either getting another brand or actually treating your health problem.