You have possibly got a problem with your spine. This may be facet joint stiffness
or a disc prolapse
. The muscles may be in spasm due to the underlying problem.
I suggest you discuss the need for an MRI with your doctor.
In the meantime, paracetamol
may help the pain. A TENS (transcutaneous nerve stimulator) could be considered as a non-drug method of pain management. Exercises to strengthen your core muscles could be suggested by a physiotherapist.
I hope this is of help.
Dr K A Pottinger