Colorectal cancers in your age is unlikely in absence of any family history.Ulcerative colitis usually presents with blood mixed stools.Crohn's disease is hard to rule out by history alone.If the pain is severe,colicky and there is weight loss/anorexia then you should undergo colonoileoscopy.
Next Steps
You can get a fecal calprotectin done.
Take treatment for fissures.
Health Tips
Avoid constipation.Contact a gastroenterologist if you have any of the alarm features like -Anorexia/Weight loss,Bleeding PR,Abdominal distension,Recurrent vomiting,Anemia.