Other headaches such as Tension Type Headache and Migraines need to be ruled out as physiotherapy will not be as effective for these primary headaches

It's very important to recognize red flag symptoms of headache that require further medical evaluation, which include:

Headaches that are getting worse over time
Severe sudden onset of severe headache
Headaches associated with high fever, stiff neck, or rash
Headache associated with neurological signs or changes in consciousness
Onset of headache after head injury
Problems with vision or profound dizziness

Injury Fact sheets - Head Neck and Spinal

Neck