What to do if i have chest pain and numb arm sometimes, could it be a blocked artery, or just stress?

Possibly: Radiating pain to l arm and jaw (mandible) is referred pain from t1-3 spinal nerve roots; these same nerve roots innervate the heart. Not all chest pain is cardiac: recall gerd, oesophageal spasm, even left-sided pneumonia can re-create similar symptoms. If sx persist, recommend an ekg and cardiac enzymes. If those are negative, then seek the care of gastroenterology.