Cord-like lump under skin on shaft

I'll try to keep this as simple as possible.

About 2 days ago I noticed that my penis was a little sore at one spot on the shaft about an inch down from the head. I thought maybe in the act of masterbating I had maybe cut it somehow. I examined and didn't see any cuts, but when I ran my finger across one small area it was irritating.

Today I became erect and when I grabbed my penis to masterbate, I instantly felt something wrong. I looked down and there appears to be this large cord-like bump that starts on the top of the penis shaft, circles around to the back and up towards the head.

It's under the skin, but you can most definitely feel something in there, it feels almost like little spongy stuff under the skin, you can move them around and such under the skin. Where it ends is right around where I remember that sensitive spot being the other day and it's a larger almost cauliflower feeling lump under the skin there.

What is this?? I've googled and looked around and started seeing cancer stuff pop up so i'm a little worried. I also don't want to go to a doctor if I don't need to and have my female doctor poking and prodding around my shaft. When I'm not erect you can definitely still see the cord-like lump if you look for it, but it's not really noticeable until erect when it's HUGE and stands out like a sore-thumb. My penis really looks deformed when erect now.

Any ideas on what I can do or check???