Why is my tire hot and smells of burning rubber?

What is your question?

My boyfriends a mechanic, but is at work, and i want answers now. While driving i smelled a burning smell of rubber, and noticed the way the car was driving, felt bumpy. I pulled into a quick shop, and checked, the tire was scorching hot. So i jacked car up and removed tire, and put my spare on. When i got home, i noticed that this tire too, is hot and smells of burnt rubber. What the heck could be going on? Thanks! And dont give me stupid answers.