Matt my experience is similar to yours. I saw four surgeons over four years. The first three made me feel like I was wasting their time. The "Three Surgical Stooges" all called my mobile hard painless lump a cyst. My training and my brain was not comfortable with this diagnosis.
The fourth surgeon "Superman" told me it is most likely a cyst but if you want it gone I'll remove it. It came back "clear cell sarcoma". A very agressive form of connective tissue cancer and the rarest of the sarcomas.
My thought process for myself, family and patients is this: Any lump,bump, sore spot, discoloration etc. must be excisionally biopsied.
I would rather see more biopsies of benign or innocent lesions than mis/undiagnosed cancers. With that said we are not bilaterally symmetrical. It is not uncommon especially in the head and neck region to have small less than 2 cm bumps under the skin or mucosa.
If you don't like not knowing what this is, insist it be biopsied. If your current Doctor won't remove it find someone who will.
I hope this helps you.

Banish the bumps,
Mike