What Causes Irregularities In Periods?

GOOD MORNING MAM I RENEE 25 YEARS FEMALE MARRIED FOR 4 YEARS I HAVE BEEN FACING PROBLEM OF IRREGULAR PERIODS MC A GAP OF 45-50 DAYS WITH 3-4 DAYS NORMAL FLOW WITH SEVERE PAIN SUBSIDES AFTER MEFTAL SPAS NOT ABLE TO CONCIEVE CAN YOU PLEASE TELL WHAT IS THE REASON FOR MY IRREGULARITIES I DID NOT CONSULT ANY DOCTOR