Sounds much like my experience! Brought small lump behind right ear to my primary care physicians attention 3 years in a row. She always dismissed it as inflammation until the last visit I told her I had another lump starting behind the left ear and the right ear lump seemed larger.
CT scan ordered (with contrast) and results were bilateral parotid tumors.
Unfortunately, in researching treatment for such tumors, much depends on the type of tumor. From the scan Dr thinks mine are Warthin tumors which are usually benign. While major surgery for all parotid tumors is recommended, there is also evidence that radio frequency ablation can shrink tumors. This in my opinion is much less invasive.