Hi and welcome to HCM,thank you for your query.
Cancer is not the first thing to think of and cancers,especially lung cancers are very rare in your age. Testicle cancer i more common but also I dont think this is likely to be malignant disease. however you should do some basic tests such as lung xray and testicular ultrasound
just to rule out some other diseases.
Wish you good health. Regards.