Please help! i need answers!?

Today in the shower I noticed my leg was sore. Like where your undies would end in the front crease. I felt it and it felt like a knot or something. Its pea sized. Its like a knot that I've gotten on the back of my neck before. But this is really sore. Its not like a pimple or boil or an ingrown hair. It's not red and or sticking out. Everything looks normal but what is it? And its not in between my legs. Its on my front side. Any help?