Go to the er or not?

Had the stomach bug for a couple days and have felt so drained. On top of that I woke up in lots of pain in my back and side. I massaged it till I could fall back to sleep. I've woke up now for the day and my back and right side are still killing me. It hurts when I breath and move in that direction. Is this normal or?

Edit* I'm 21 weeks pregnant.