Heather,
I know the constipation pain you're talking about
! It's awful! I, too, had always tended toward constipation, but going gluten-free for a month made it 10X worse. I kept increasing my fiber - whole grains, fruit, veggies, bran...it got worse and worse.
I started looking online, because I was desperate for some relief.
What helped me - believe it or not - was to eat more SOLUBLE fiber and less insoluble fiber. (There's a long thread about
this diet on the IBS forum here at Healingwell...it's written by a Heather Van Vorous, I think.) I'm sure it's not the answer for everyone, but I'm just throwing it out there as an option to try.
Ok, I just looked at that site and it seems to be gone, but if you just Google her name, you can access it.
I also take Miralax and Citrucel every day.
Good luck!!
Debbie