Weird gross painful mystery wound

So, a few days ago I noticed that I have this on the back of my right shoulder:
Actually you know what, about a week ago my friend pointed it out to me, I think I forgot about it and then noticed it’s still there some days later. He took a picture of it for me when he saw it, it was smaller when he first noticed it
It’s pretty tender and painful, the inside of my jacket rubbing against it feels very uncomfortable. I have no idea what it even is… I’m thinking of going to urgent care for it, make sure it’s not some serious infection or something. Have you ever seen something like it, or know what it could be? It feels like there’s a bit of leaking serous fluid under the crusty part. I’ve never had anything like it before.

Last night my friend accidentally bumped into me and the wound got partially rubbed/peeled off

looks fucking gross, I know. I’m gonna go to urgent care in like maybe a couple hours.