I have a persistent stomach ache/tightening feeling and my latest bowl movement consisted of a moderate amount of blood within the bowl and noodle-like stool. i'm worried if this is something serious. if it isn't, is there any way to help the pain?

Right now the most important thing is to establish an accurate diagnosis. I would recommend that you see your primary doctor face to face for an examination and consideration of a consult to a gastroenterologist for either colonoscopy or flexible sigmoidoscopy. At your age the bleeding is most likely from hemorrhoids or a fissure around the anus. Your doctor can help establish a diagnosis.