Worried i have coronary arteries disease.i have normal blood work.im 19.when i walk for a bit,start to get chest discomfort/pressure kinda.im worried.

Overlapping symptoms: It's a bit of an overreach for you to take symptoms common to many issues & go to a diagnosis common to the over 50 crowd. If you had blood work for chest pain it looks at any evidence of heart injury. No evidence + age means you need to focus on something else. Write down all your symptoms with duration & any triggering factors you can think of. Then schedule a time & go over it with your doc.