Have you tried different diets? Like people who are not absorbing their nutrients can be gluten intollerant. I would follow a gluten free diet and see if you have any changes. It took me 2 months off of gluten before I felt a difference. So it might be a long term change. After one year on this diet I can now take my supplements and feel a difference. It seems from what I read that gluten damages the lining of the intestines that absorb nutrients into the body. If they have a group that discusses this, it might be more helpful to check them out. I am a new member of this website.
I'm seeing a naturopath for IBS with constipation. I am trying the things she suggested. I take one Oregon Grape (an herbal supplement) with each meal. I use flaxseed meal instead of psyllium fiber, because psyllium irritates my GERD. I take 2 oz of aloe juice mixed with water or juice as often as the instructions say on the bottle. I have noticed some instant soothing of that familiar colon pain you're talking about, if nothing else with the aloe vera juice. The aloe is supposed to do three jobs here: Help with the colon pain, help soothe the GERD and actually help with the constipation. I am taking probiotics and will be trying these enzymes she wants me to try instead, so we'll know which one is doing the job. I am also talking some slippery elm in capsules. It is important to follow the directions and take it with WARM water. I noticed something here, too, that should be of interest to you: the warm water seems to be soothing to the colon, too.
Prunes only help short term, and I'm still left with the colon pain afterwards. The solutions I'm trying are meant to be long-term. One other thing I've been doing is taking ONE cascara sagrada every night before I go to bed. The trouble with taking two of them is that they end up working too well, because they are a natural laxative. This is only helpful on occasion, not regularly, because of obvious nutritional issues and using such an amount of laxatives will lead to dehydration and to new issues you don't already have with your kidneys. So, don't do that. Taking ONE seems to just draw SOME water into the colon as a stool softener, rather than a stool liquifier. This is an important distinction as already noted above.
Also, see if not eating gluten and dairy in your diet will help you out any or not.
I too have had to depend on laxatives to have bowel movements. Started having stomach pain on right side in Dec.08 and went to doc. did xray said I was compacted, was told to get 2 bottles of Magnesuim Cytrate (in laxatives in drug store) and 2 Fleet enemas. I did and after the 2 enemas drank the 2 bottles of mc. The original flavor (kinda lemon-lime) was best for me. I drank it with a straw and took like 5 big swallows at a time until finished (also took 5-10 mins breaks in between). It took about 7 hours before it started working on me and there was no cramping, just watery stool (that's what it is suppose to be) and you need to be within 10 to 20 ft of toilet because when the urge comes it's immediate!! I went for 4 to 5 hours and felt much better only to have the problem again in Jan.09. Did 2 ct scans and a colonoscopy and didnt' find anything. The GI doc put me on Amitiza but did not help so today (a week after my colonoscopy) she took me off Amitiza and started me on 3 Metamucil tablets every morning and 1 Colace, then 1 Colace each night as well. I'm waiting to see what happens next...good luck to you.