Random patches popping up?

I’ve had this dark patch pop up on the side of my neck a few weeks ago. It doesn’t hurt itch, nothing. It’s just there. Then today I was getting ready to shower and noticed I have 3 small pink patches between my boobs. I’m also 20 weeks pregnant. I’m not sure if pregnancy has to do with this or what it is. Any ideas?? I do have a skin tag beneath my right boob that I’ve had for as long as I can remember and after having my first child it got a little bigger so that’s why I’m not sure if it has to do with pregnancy.