Definitely sounds like your self diagnosis of varicocele could be right on the money. https://www.mayoclinic.org/diseases-conditions/varicocele/symptoms-causes/syc-20378771 I'd get checked by your doctor. Often they do not treat and watch. If you are a man wanting to have a baby and have low sperm count or something like that because of it, they might recommend surgery.
Here are the 5 signs of a varicocele, which include a scrotal mass, heavy sensation, enlarged veins, dull or sharp pain, and infertility issues. Varicocele is typically asymptomatic, but it may become more visible over time. When a varicocele reaches a certain size, men may begin to experience symptoms.
Unfortunately, if they do diagnose you with this, they don't go away on their own. You would probably eventually want to surgically remedy it.
With all that said, there are also other things that can cause your symptoms. Read this article for ideas and see if anything else seems plausible. https://my.clevelandclinic.org/health/symptoms/16292-testicular-pain