Should i be concerned if havent had period in 4 months; i know about cycle change and stress being a factor. but recently ive started have cramp like pains but intense ?

Time to see doctor: In a woman with regular periods, some causes of a late period include: excessive weight loss or weight gain, increased exercising, emotional stress, having an illness, traveling, medicines (like birth control pills), hormonal imbalances, etc… Seeing a doctor for evaluation is a good idea if more than 3 periods are missed. Pregnancy is a common cause of missed periods, so a pregnancy test is wise.