Hi Seabreeze. It's really hard to know if you have a muscle issue going on, if it's related to a possible spine issue, or a combo of the two.
It's not at all uncommon to take a conservative approach to things. Most often, given a little time, things get better and tend to resolve on their own. I am not saying you should just sit there and wallow in your pain. I am just saying that it's "normal" for the doctor to start off with the "easy" or "do little" approach first, then if the patient shows little or no improvement, to look more into the situation.
If you have the ability to see a specialist on your own, without a referral from your regular MD, then make an appointment with an orthopedic surgeon. A back surgeon need not be immediately sought at this time, unless you have been diagnosed with a spinal issue. A regular ortho can easily diagnose and is much more intune to the muscle and skeletal being than a regular MD.
If it's not overly serious be it muscular or skeletal, you may only need some stronger pain meds, possibly an anti-inflammatory, and some PT to put you right again. A CT Scan or MRI could tell alot more as to what may or may not be going on.
Hang in there and keep us posted on how you are doing.