Should I be referred to an oncologist if I have a benign tumor?

Not usually. Oncologists are specialists in treating cancers (malignant tumors), generally with drugs (chemotherapy). Benign tumors don't need chemotherapy; they may need treatment with surgery, or not; depends on the tumor, type, size, location.
No. In general, but it would be better to describe the benign tumor. A lipoma? A breast cyst? Oncologist understand lumps, but make a living administering chemotherapy.