I definitely pulled my entire right trap from my neck to the middle of my back in pincha mayurasana in yoga this morning. It's such a strange feeling because I've been active my whole life and pulling muscles has never been a problem, but being on your head and on your forearms with your legs in the air and then squeezing your elbows together did something to the top of my back. I felt the pain instantly. My instructor did some crazy shit and made my neck crack both ways, popped all of the bones in my upper back, then jammed his thumb into my muscles. It helped, but it didn't. Now I have a towel with ice strapped to my back.