Hi there Dec1an...when we strain to pass motion it can cause piles [haemorrhoids]  they can be internal and external..this can cause blood on the paper or in the toilet bowl..keeping your bowel movements regular,  preventing constipation is important..as you have had the same issue for a couple of years you might want to think about your diet and intake of fluids ...when stools are hard and difficult to pass it can be due to lack of fluid in the diet...hopefully you have someone to share your concerns with and perhaps make an appt with your Doctor to put your kind at rest..

Hello and thanks for posting

It can be a worry to see some blood on the toilet tissue and after having a poo but there can be many reasons for this and most will be harmless.

At your age any cancer would be extremely rare and is most likely because you have strained to pass the stool causing a little tear.

Try to make sure you are eating plenty of fibre and drinking enough water to prevent constipation.

If the bleeding continues or you remain worried do speak to a parent or trusted adult about this and if needed they can arrange a doctors appointment so you can be assessed properly. 

I hope things improve soon. 

Kind regards,

Celene