Back pain is extremely common, often at the base of the spine. It is important to understand your pain including the fact that it is your brain that creates the experience of pain as a protective measure when there is a perceived threat. This is in addition to a number of other responses including changes in the way we move, activities in the different branches of the nervous system and immune reactions.
It would be useful to know more including how long you have had the symptoms and the story behind your pain (e.g, an injury, gradual onset).

As Mr. Khan states, back pain is common and is for the most part self-limiting. Back pain that does not appear to be getting better in 2-3 weeks with self care such as heat or ice, over the counter medicine and activity modification deserves examination by a health practitioner. However, I would not recommend an x-ray or MRI be done unless there were red flags that warrant it or you did not respond to conservative treatment in a reasonable period of time. Studies have shown that the results of these tests do not predict the outcome of treatment. That is, you may have lots of spinal changes to point out on the exam, but that really doesn't matter. These tests either expose you to radiation or are expensive and many people fall victim to the belief that they can't get better once they are told the results because they believe that there back is too screwed up. Good Luck.