Hello and welcome to HCM
A mass over mastoid can occur due to many reasons- mastoiditis
(inflammation of the mastoid air cells), growth of the mastoid bone, tumor
of ear extending into the mastoid, underluing pathology of temporal lobe
of the brain to name a few.
Since, it is associated with local pain, eye symptoms and headache a more extensive pathology is suspected- something concerning the brain parenchyma.
However, it can only be acertained by MRI
Get the investigation done and your treating doctor will guide further.
Wish you good health
Dr Shailja P Wahal