Question: What diagnosis should I use for myofascial pain or myofascial discomfort? South Carolina Subscriber Answer: The ICD-9 index for "Pain, muscle" directs you to 729.1 (Myalgia and myositis, unspecified), so that should be your first consideration.- Depending on your neurosurgeon's documentation, however, you might be able to submit a diagnosis that's more specific to the patient's pain, such as 724.2 (Lumbago), if the physician states that the patient's pain is in the low back region.