On and off rectal bleeding after bowel movements for the last 5 years. What type of doctor do I see?

Several. As I have said many times before on healthtap...No amount of bleeding from the rectum is normal or should be ignored. See either a colorectal surgeon or a good gastroenterologist and see them sooner rather than later. This needs to be properly evaluated, specially if you are over 50 or are at risk for colorectal cancer..
Pediatrician first. First the pediatrician after examination and evaluation will refer to right specialist if needed.

Related Questions

On and off rectal bleeding after bowel movement for the last 10 years. Should have seen a doctor?

Yes you should. You must see your doctor, any bleeding per rectum has to be considered as malignant till proven other wise by tests, even if it looks like hemorrhoids, march is colorectal cancer prevention month and you must see your doctor.
Yes. Assuming the pattern hasn't changed it is probably not serious, however since you are used to the bleeding, you would not be alerted to another more serious cause of bleeding. So, yes, you should be checked and have more serious sources of bleeding eliminated or diagnosed, usually by colonoscopy at the least.

Why have I had on and off rectal bleeding after bowel movement for the last 10 years?

See a doctor. Get an examination. Maybe hemorrhoids, but need evaluation for other things such as colon polyps or colon cancer.

My 3 year old son has rectal bleeding when he has a bowel movement?

Constipation. Chronic and moderate severity is causing the rectal bleeding. You need to be aggressive with managing this problem. Else he will suffer from fecal soiling and UTI as a consequence. He will be scared to move his bowels especially with associated abdominal pain and rectal pain. Get him checked by his pediatrician.