<s>[INST] I have been having vertigo, dizziness, and light-headedness off and on for a couple of weeks. Now I have pain in the lymph nodes in the right side of my neck. I also have a mass the size of a walnut in the back of my head that has been there for at least six or eight months. [/INST] Hi.Tumors in posterior fossa at the base of neck cause persistent vertigo and dizziness .Cause are - Brainstem compressionVestibular nerve involvementThanks </s>