Hi, I was out shopping today and I went to sit in a hard chair. It ended up being really soft so when I sat I kind of fell back and twisted a little. At the time I didn't feel anything until I stood up and then I had a bad pain in my sternum, justto thr left of it. I couldn't breath and it felt like something was pulling or stuck. It hurts when I barely push on it or moveor bend over. What did I do??     

Thanks,
Misty