Brief Answer:
Fissure in ano/hemorrhoids

Detailed Answer:
Hello,
Thank you for your query.
I'm Dr. Shuba Hariprasad and will be answering your query today.

Your symptoms would lead me to primarily rule out an anal fissure or hemorrhoids and gastritis.

I would:
-get a detailed medical, personal and family medical history.
- do a clinical exam to check for signs or gastritis, and a rectal exam to look for source of bleeding.
-do basic blood work (complete blood count, clotting parameters, kidney and liver function tests)
- if indicated, a colonoscopy and endoscopy to rule out other possible lesions that can cause discomfort and bleeding.

Any rectal bleed must be immediately investigated as it is not normal to bleed. You mentioned a colonoscopy, was an endoscopy done?
Please see your doctor right away/go to the ER if bleeding continues
The urge to pass stools is probably due to the spasm of the anal sphincter. Don't try to strain or put digitally manipulate.

Hope this helps. Please let me if there is anything else I can help you with.
If not, please close this discussion and rate my answer.
Wish you good health.
Regards,
Dr. Shuba Hariprasad

---