I don't know if this helps at all, but I think I used to get the same symptom.
I would pass a toilet-bowl-filling bowel movement and the feel cold and weak, often feeling a sort of shiver in my lower back or the the space in my body cavity just in front of it. I guess it was in or around the bowel that had just been emptied.
Sometimes this was associated with diarrhoea but sometimes it was with more normal bowel movements.
I don't know when it stopped, but it was probably about 12 - 18mnths ago. And therefore do not know why it stopped.
But I have I have done a lot of work with diet.
Weston A price >> primal >> GAPS >> ketogenic primal >> ketogenic Autoimmune Paleo. Working around the 3 ideas: that I need to avoid some foods I react badly to; that I need to eat a wide range of dietary fibres; and to take probiotics or probiotic foods.
I get the fibre and probiotics from food now, but have used commercial probiotics and isolated fibre.
I found that GAPS really did not work for me, I just fell into a mental fog so deep that I could not even understand what I was doing.
Having a very low carb but high fibre diet worked better, but I had some issues with fungal infections. These seem to have disappeared now that I am taking Betaine HCL to acidify my stomach.
My stools are not perfect, not even good, but constipation seems to only be associated with testing foods I don't tolerate (twice since Easter). Diarrhoea is more common maybe a day a week, and my stools are definitely not consistent, but I no longer have the symptoms you mentioned.
Oh, and this may be TMI but I wish someone had shared it with me. When constipation does strike I throw dignity to the wind and squat on the shower recess floor, use my fingers if need be, and clean it up when I'm done. Still painful, but less so, and there is rarely any blood.
