Just thank god its not lower back, those never go away. Upper back pains go away with time. A doctor will probably give you some pain killers and tell you to rest. I would recommend a deep tissue massage. The normally cost about 60 dollars for an hour but are well worth it. If nothing else, it feels really good. If that doesn't work, go to the doctor. A chiropractor sometimes helps also but alot of them are quacks that think they can cure cancer. Health issurance usually covers it though.
