First - I doubt that you're going crazy but you probably are fed up with all of this!!

Next it could be from nerve damage but if you're straining & constipated that would make the problems caused by the nerve damage worse.

Third, how long have you had constipation problems? How long since the lower back injury? The time frame for both affects answers/help etc - assuming there is any of course - sometimes we just have to learn to live with things. But please answer the above questions - also what sort of diet do youo eat & what if any exercise do you get?

i have something like what you're dealing with. about eight mos ago i was constipated from the atkins diet and strained during bowel movements. about a week or so after i noticed this annoying feeling it was as though stool was stuck just at the end of the bowel. i would make a bowel movement and it felt like a small size stool was being left behind. sometime if felt like i had stool stuck just on the out side of the rectal, like i failed to wipe myself. as time went on it would let up but never really go away. even when i would have diarrah i thought i would get whatever there out but the feeling would still be around. To pass gas would seem to give a little relief but only for a few minutes sometimes not at all. i have since had a colonoscopy and nothing was found. the dr stated if i still had the problem he would have me see a dr that examines the anal muscle. so now i'm waiting for that appointment. there was one other thing that i noticed, at the base of my neck if i move my head down toward my chest there is a traveling tingle which runs down the back and causes a tingle at the anus. At time i thought it made the anus fell numb like some type of paralysis. there use to be an intermittent vibration that would happen in the pelvic area which i though was very strange. it started one morning when my cycle started and stated around for two months or more.. i thought whatever this is that i'm dealing with it must be related to a damage nerve. at some point i thought my tail bone was the problem by pressing on the rectum. that would explain the traveling tingle down to the anus. anyway my dr said it's not the tail bone. i just had surgery unrelated to this but it was in the area, i had my uterus out due to fibroids. i was hoping this would relieve the pressure on the anus since everything was being push on due to the fibroiods being so large, but it only gave me a little relief. someone has got to know what this is!!! i know i'm not the only one with the symptoms i have......