What could a firm tubular feeling at bottom right posterior side of testicle be? Also have some lower ab pain. Doc didn't feel anything alarming@ exam

Epididymis. The epididymis is a normal tubular structure that can be felt above and below the testis on either side. If it's inflamed it sometimes becomes an large and tender. If there's any question about irregularity on physical exam, a scrotal ultrasound can be performed.