Hard stool occurs due to reduced reduced water content in rectum, which makes movement of stool to rectum very difficult. Since you have problem of constipation from childhood, so this is obviously a case of chronic constipation. Chronic constipation is a high risk factor for diseases as inflammatory bowel syndrome, colon cancer, hypothyroidism and
diabetes. You should check laboratically to rule out chance of colon cancer or other serious disease. If you are taking iron supplement, than hold it for few weeks, untill bowel habits start to become regular. When your toilet habit starts to come everyday, make a good morning habit of going to toilet regularly, as colonic movement is very active during morning. When you get the urge to toilet initially, donot avoid it due to any excuse. Take advantage of the colonic reflex when it comes initially, otherwise stool content gets more harder in rectum due to fast reabsorption of water in large intestine. Start practicing yoga, which will stimulate brain, reflexes and regulate hormones properly. You should take more fibre diet and plenty of fluids, which will cure problems of constipation. If you are suffering from stress or anxiety, than take measures to avoid it as stress or anxiety causes constipation. Treatment should be started if constipation remains more than a week or abdominal distension occurs or black tardy stool is passed or combination of all these. In my opinion, you should take juice of bael, whole mango fruit, pineapple or guava. Tab. Dulcolax 2tab at bedtime when constipation occurs. You may also consult gastroenterologist anytime and check for colonoscopy and sigmoidoscopy for knowing cause of chronic constipation.