Back pain can be caused by many things - arthritis (rheumatoid or osteo), disc problems, muscle tension, etc.  You don't mention whether you have seen a doctor about this, but I suggest that you do so.  Your doctor should be able to run some tests that might be helpful in identifying the problem.  Until you get a diagnosis, you may be able to manage the pain somewhat by using ice packs or heat treatment and strengthening your muscles by swimming or doing gentle exercises in water.  Massage may be helpful, as well.

I hope you get an answer soon.

Upper back pain is much more uncommon than lower back pain, but can be very debilitating.  It is frequently caused by muscular problems, and can be aggravated by carrying heavy loads, such as backpacks in school age children and teens.  It usually is not caused by bone or spine problems, due to the strength and stability of the upper back.  If you are impaired and it is affecting your daily life, you should go see an orthopedist to see what they can do.