My son and my daughter had this very same thing happen to them and it was backed up stool. It took my son about six months of stool softener, fiber, yogurt, and prune juice to get his system back to normal. He was 17.
My 20 yo daughter is going through this now. Lots of bloating, cramping, abdominal, pain, stomach aches, etc. She was referred to a colorectal surgeon who didn't find anything during her scope. It's been about 4 months for her. She is on heavy duty probiotics right now.
I would be most concerned about blood in your stool. Rectal cancer and hemorrhoids can leave bright red blood in stools. Colon cancer further up the colon may leave dark red blood or no visible blood at all. Your other symptoms aren't consistent with rectal cancer, at least in my experience, so bright red blood shouldn't be there with a tumor far up the colon. Sometimes, red colored foods can just look like blood. You really want to save the stool and have it tested if you ever see that and you didn't eat anything like tomatoes the previous few days. Blood in stool should never be taken lightly, regardless of your age.
Your spine pain wouldn't have anything to do with colon cancer, from what I can see.
I would ask for a referral from your primary care doctor to a colorectal surgeon. They have lots of experience with colon cancer and can help you rule that out once and for all so you can stop worrying about it. Lots of stress can cause digestive problems like you are describing. That's probably all it is.
47yo single mom of 4 (24, 21, 18, 16) at Dx
6/13 - RC T4b IIIc 5LNs on PET CEA 5.4
8/13 - Finish chemorad
10/13 - APR/hyst+ovaries/perm colostomy 2/12 nodes+
6/14 - Finish Xelox 6 rds
1/15 - CT clear CEA 0.2
10/15 - CT/MRI clear CEA 0.7
4/16 - CT clear
10/16 - CT/MRI clear CEA 0.6
5/17 - PET clear? Follow up MRI to verify inflammation