Small hard non movable lump directly on collar bone where it meets my shoulder. been there for a few months no injurys to it before. what coul it be?

Lipoma: It is probably a lipoma but that can only be confirmed by physical examination.A lipoma is a growth of fat cells in a thin, fibrous capsule usually found just below the skin. Lipomas are found most often on the torso, neck, upper thighs, upper arms, and armpits, but they can occur almost anywhere and are non cancerous.Consult your physician to confirm the diagnosis of lipoma.

Ac joint: The collar bone meets the shoulder at the acromioclavicular joint. That joint can get swollen, inflamed, or even arthritic among multiple other reasons it may get enlarged. Usually an exam and xray can determine the cause and if any treatment is indicated. Thank you for the question.