dear user about your question i would like to tell you that constipation is common problem and at the same time the treatment is simple but always be losen....constipation mainly refer to bad food style that may contain starch or rice or tea drinking and less vegetables and less fruits....this can make severe constipation for the child ...there may be no pathogenic disease causing that but unhealthy food enough to be the cause...iron will not give improvement it some tumes make the problem worse so you can change his food style to food containing high fibers as fruits and vegetables with less rice less besquit less tea...you will find him after short time having normal defecation and the constipation ended gradually and anal pain will relieve as the constipation is the main cause of this severe pain....so treatment is simple but alot of people think that drugs will be good...healthy food is very effective and he will be fine.....i hope that helps you