I think I pulled a muscle in my upper back?

I don't know how I did it. Earler today it was hurting but it was bearable. It hurt but after awhile the pain dulled. After hours went by the pain returned only this time so much worse. The pain was so severe. It is on the upper right side near my shoulder blade. Please tell me anything I can do to make it better. I'm laying in bed now. It still hurts pretty bad but if I lay still it's bearable. What should I do???