Thank you for the query.
Described by you symptoms are very often for diseases causing impeded stool passage. It can be inflammatory intestine diseases (like Crohn`s disease, ulcerative colitis
) and colon cancer
. As you are young person, cancer is less probable.
Your symptoms should be not neglected and colonoscopy
is advisable as soon as possible. Your fatigue
and light headed is a sign of anemia due to large intestine bleeding.
You should also have fool blood work and abdominal ultrasound or CT.
Hope this will help. Feel free to ask further questions.