Your symptoms didnt' sound like STD (chancroid or any other) then and they don't sound like STD now. Chancroid generally occurs on the penis itself, not the pubic area--and in the U.S. fewer than 50 cases are reported each year, most of those aquired overseas.
See a health care orivuderr about your symptoms, but accept the reassurance when s/he also says you don't have an STD. I know of no disease characterized by excessive yawning, except being sleepy--or unusually anxious or stressed.
Good luck--- HHH, MD