I've been in physio for 10 weeks for radial nerve compression in my neck, but still have symptoms. shouldn't it be helping by now?

See below: It would be unusual to compress radial nerve at the neck, due to the origin of this nerve from the brachial plexus. You might benefit from seeing neurologist for evaluation and establishing proper diagnosis.

Not necessarily : A physical compression due to cervical disc herniation may not get better even with pt. If your symptoms of radiculopathy is not relieved following weeks of conservative therapy then seeking a neurosurgical evaluation may be necessary.