There are many causes for low back pain. However, it's recommended that you take a few NSAIDs (non-steroidal anti-inflammatory drugs) such as Tylenol, Advil, Aleve, etc. for relief of an initial back pain. You may then check with your healthcare provider to rule out any disc damage. Providing there is no serious injury or disc damage, there are many lower back stretches that you can perform to help strengthen and increase flexibility and range of motion of your back.
You might also want to adjust your sleeping habits, change your mattress and practice correct sitting and standing habits. Pay close attention to the shoes you wear(if heels are too high, this can be a problem). These are just a few of the many things you can do to help with your back pain.