I feel for you and your son A.. I have been going through this same thing with my almost 2 yr old daughter since she was born. She was on Miralax for about 3 month daily and it still did not seem to help. Besides using a laxative or stimulant is no good long term for the bowels as it makes the bowels become dependent on having the medicine to go to the bathroom. My daughter too suffered through the cycle of constipation, diarhea, fear of pooping. She would constantly hold it it because she was afraid to go, thereby causing her to be constipated, which made the poop harder and hurt and then started the cycle all over again. I have tried everything and in the end the only thing that has worked for us is to cut her dairy and have her drink a new soy milk I found called "Silk plus Fiber" I can usually find it at Target or Whole Foods, sometimes Dominicks. I don't let her drink any cow's milk, but I do let her have other regular dairy in cheese or yogurt. Each serving of the Silk plus Fiber has 5 grams of Fiber in it. She drinks two glasses a day and loves it. It is Vanilla flavored. We started this about 1 month ago and now she has gone poop every day or every other day and the poop is soft but not diarrhea. This has really helped ease her fear of going and she doesn't try and hold it in as much. She hasn't had to have the Miralax once. Now she will even eat a little soy pudding or yogurt since she has grown to like the taste. This has been the best for us and no laxative which I love. Give it a try, it can't hurt! Good luck. As for the rash sometimes what works best for my daughter is a thick coat of vaseline with some good old fashioned corn starch in there. Also pick up some lotrimin AF (athletes's foot cream) and apply this twice a day as the rash may have a fungus to it. You can also put on some monistat cream in case yeast is the culprit. The best thing for diaper rash is to keep it as dry and clean as possible. Warm bath at night to sooth and a thick covering of vaseline or cream at every change while the rash is present to form a barrier between skin and poop. Stop with any baby wipes (even fragrance free ones) and use a warm wet wash cloth til it clears up. Fan his butt with the new diaper to dry it before closing it up. (moisture is bad for the rash)Also try and give him a little time with out the diaper on every night to air out a bit.