Hi,

I also had a bowel resection recently (30th May)for endo but had the opposite problem to you. After the initial bowel movement in hospital I was constipated until yesterday. This caused pain in my lower back and legs and doc was concerned as he said that is the worst thing to have after bowel resection. I have been living on high fibre diet to fix problem. Thankfully this seems to have been resolved (although still isn't normal) and back pain has reduced.
I guess we all react differently to surgery and our bodies take a while to recover!

Hope your feeling better soon.