I'm 27 years old and for the last month i've noticed a bright reddish colored small chunk or small streak on my toilet paper after b.m.

Probably hemorrhoid: Bright red blood on toilet paper is often due to bleeding from hemorrhoidal tissue that surrounds the opening of your anus. If you feel a bump when you wipe, it is most likely an external hemorrhoid. If there is nothing palpable, most likely an internal hemorrhoid. There are other causes but you should try increasing fiber in your diet to avoid straining. A quick md check is a good idea.