Normal value for CK-MB is generally 5-25 IU/l.
So your level is within normal limits.
Next Steps
It is most commonly done to evaluate cause of chest pain & rule out heart attack in co-relation with few other tests.
It also rises with-
Recent muscle injuries, trauma, burns, and electrocution,myopathies.
Strenuous exercise
Prolonged surgeries
Renal failure etc.