You should contact the va hosp near you, and take the Agent Orange test..consisting of a blood test, chest xray, and a nurse asking you were you were in Vietnam, dates etc....you'll get a letter in about two weeks with their findings...with the letter go to a primary dr in va and show him the letter which in turn he'll assign you to a specialist in the field.... The dr is required by law to write a letter on his letterhead ,va or private, in support of your claim..
good luck..