Does abdominal pain mean that birth control pills are not working or fertilization has occurred?

Yes I take the tablets every day at the same time without skipping

To @Gabriela: as I have already explained, light, occasional abdominal pain does not allow you to answer the question of whether the pills work for you. These are non-specific symptoms that can indicate almost any health problem, the occurrence of an adverse effect of the drug, and sometimes they are a physiological reaction and do not have to testify to anything at all. If you use it correctly, it should be assumed that they work in accordance with the effectiveness declared by the manufacturer. There are no tools that allow the patient to check the effectiveness of contraceptive pills at home. If this topic bothers you excessively, you can make an appointment with an ultrasound - a thin endometrium and no traces of ovarian activity will speak for the fact that contraceptive pills exert changes in the reproductive system.

I ask because sometimes my stomach hurts slightly and I wonder if then the tablets work