Whats the signs of esophageal cancer and lung cancer. Whats the chances I may have it. Main probs r spitting up little blood and constant burping?

GI symptoms. How much a "little blood" actually is depends on many things. Simple tests can detect larger blood loss, usually not the case in the youngster. The source of the blood in a young patient is important. Is it teeth, gums, sinuses, or is it further down the line, like esophagus or stomach? A good exam and a stool blood exam is also in order.
ESOPHAGEAL. May be asymptomatic until late!difficulty swallowing, heart burn weight loss history of gastritis barrett's esophagus and esophagitis smoking alcohol lung may be asymptomatic until late cough, cough blood short of breath chest wall or neck pain depending on location weight los smoker! 80 %.
At the age of 20 ? What at your age ? , look for some thing simple , like peptic ulcer with gerds etc see your doctor get investigated and cured , .