I have a 4x3mm sub plural nodule lower right lobe w/family history of lung and colon cancer. Should I get further testing?

What were you told? These little nodules are extremely common especially in areas where histoplasmosis is endemic, like my home in Kansas. If you look hard enough, probably a majority of folks have them. Unless your radiologist recommends an attempt at a biopsy, I'd forget about it or as maximum monitor it by imaging. There's really no test except biospy; and it's too small to hit easily with a needle.