What Causes All Over Body Aches?

My whole body aches! At first it started with my asthma becoming so bad I had to go to the ER but they said nothing was wrong, it s been over 48 hours and I m not any better but now every single muscle in my body hurts. It hurts to walk, bend over, sometimes sit, lay down. I just ache all over. And I don t feel very good. what should I do?