Welcome to the forum.
So sorry to hear you have cancer, tough to deal with.
This other issue could be anything from an inner ear infection, to a pinched nerve in your neck, to the stress of the cancer diagnosis.
I think a visit to your family doctor or ENT will help clear it up.
Moderator - Depression
"...when the gift of sight is cause enough for jubilation."
Billy Collins from the poem. HIGH
DX: reverse Trigeminal Neuralgia;Cluster headaches; Atypical face pain;Hemicrania Continua; raynauds;complex PTSD; recurring MDD,disassociative disorder;