The lump cannot cause your migraines
if it's been there for years, then it's not likely to give your problems. Cutting it out could give you more problems, from complications of the surgery.
Ask your doctor
She knows nothing. At the very least, if you cannot wear glasses because of a lump on your ear, then that simply can be the cause of a migrane.
Most definitely, my opinion is, that you have something removed if it is causing you problems. This sounds so simple, it is subcutaneous not a tumor in the middle of your brain!
Why wouldn't you want it removed? How many problems can a minor surgical procedure like that cause you? At the very most, you may have to take an antibiotic. OMG, how could you ever handle that? LOL!
Wish you the best.
You don't want it to grow like this do you?
Sure hope this isn't an issue for you!