Difficulty in getting pregnant for 3 years with severe period pain can be due to conditions like endometriosis, hormonal imbalance, or ovulation issues affecting fertility. Focus on a healthy routine with a balanced diet, regular exercise, and stress management, and track your ovulatory cycle to improve your chances. Maintain a healthy weight, have regular intercourse around fertile days, and avoid smoking or alcohol. Since this has been long with painful periods, consult a doctor to check the cause and guide proper fertility treatment.