Recently started taking birth control (qlaira). ever since i started i havent had my period. took a pregnancy and it came out negative. i also have a slight pain/discomfort by my left boob/chest. what could this be due to ?

Irregular period: Irregular periods following introduction of hormonal birth control is very common. It reflects your body's efforts to recalibrate hormones with new levels. It can take up to 3 months to resume normal cycles. Additional side effects include painful or tender breasts, nausea/vomiting, headache, painful menstruation, changes in weight. Talk to your Dr if this persists.