30 year old male has lower extreme right side abdominal and lower back pain suddenly followed by blood in stool. what could cause this?

See a doctor: There are a several things that can give these symptoms. The best thing to do is to seek immediate attention with a physician. I would urge him to go to the nearest emergency department for further evaluation.

Needs evaluation: Extreme pain and blood in stool are serious concerns that warrant examination to find the cause. In a male, most common cause of extreme pain is passing a kidney stone, but that doesn't cause blood in stool (hemorrhoids do that, and are very common). Appendicitis has other symptoms. Bowel torsion is very painful, but rare without underlying cause. Ulcerative colitis can cause both, has other sx