What is an unmovable painless lump on upper back be?

An unmovable painless lump in the upper back can be a lipoma, which is a benign fatty growth. It can also be a cyst, a collection of fluid enclosed within a sac, or a tumor, a growth of abnormal cells. However, it is important to note that the only way to determine the nature of the lump is to consult a doctor. The doctor will be able to examine the lump, order imaging tests if necessary, and recommend treatment if needed.