I have a hard, painless immovable swollen node behind right ear. dr was concerned and said if doesn't go down in a week need to get tests. cancer?

ENT evaluation first: Lymph nodes act as filters to trap and destroy infection and prevent it from spreading. The nodes behind the ear can become enlarged from infections of the ear canal, scalp and possibly other sites. The fact that it is hard and painless is somewhat concerning. If it doesn't get smaller a referral for a careful ENT evaluation should be done first, and if no malignancy is seen a biopsy is in order.