My 15 son found a small bump in his testical, saw dr and had ultra sound, but .. nothing just told to wear tighter underwear? what else to do?

If it is normal...: If on the ultrasound scan and at the urologist's visit, the conclusion was that the bump is a normal thing, then one can go about life as if there was no bump. That means seeing the pediatrician or family medicine doctor for annual check-ups, and asking the doctor to check the testicles at each check-up. If the bump changes or new bumps appear, one should see the doctor sooner, again.

Would just observe for now since his test results were negative. If the bump gets bigger, tender to touch , color change, has fever , I would have it checked again when this happens.