How did you find this out? Usually they are paired. Normally at the back. They can be different sizes, that's not uncommon. We can have an anomaly such as this and all can be fine. Your varicocele is probably the true concern. What does your doctor say about this? Here is an article to read about these and what your options are. https://www.mayoclinic.org/diseases-conditions/varicocele/symptoms-causes/syc-20378771 Usually it doesn't need treated but you want to talk to your doctor about the discomfort.