Pain in left Testicle slightly piercing, but achy!

Hi all, I've been experiencing a pain in my left testicle which just started thismorning. It's restricting my movement, I can't walk properly or even sit down without it hurting. I can't describe the pain, it's slightly piercing, but achy. When I first felt it, it also felt like it transferred itself to the left side of my stomach, and just above my anus. I'm not worried just yet, but I do want to know if it's something I should be worried about?

Thanks for your time!