--do imply a compressive effect that increases or decreases with mechanical position changes. This may be in the cervical spine, or it may be in the nerve pathways farther down--the elbow and wrist are particularly sensitive choke points. Or it may involve multiple areas.

And, unfortunately, chemotherapy is notoriously neurotoxic. The effects generally occur during the therapy, with some improvement over time after the chemo is stopped, but not always.

You may be experiencing what is known as "double crush phenomenon"--nerves already compromised by some systemic cause, such as chemo, are then compressed mechanically and the symptomology is "greater then the sum of the parts". Have you had any imaging or nerve studies to see if there is compression, and where it might be coming from? It would seem a cervical MRI would be in order, as would a nerve conduction study and electromyography of the limbs involved.