What Causes Itching In My Penis?

Hello I am a teenager and want to ask someone on the internet if my penis is fine before having to have a doctor take a look. So for a couple says now ma penis has been itchy along with bumps on the opposite of my elbow? I don t know what s it s called but whatever that is on the other side of ma elbow I got some itchy dots and bumps that won t leave. I also have the same hing on the opposite of my knee. I don t know if these two things are connected but whatevsers Jock Itch?