The clavicle bulge may be large on one side and small on the other due to congenital developmental abnormalities, uneven stress on the sternoclavicular joint, and improper sleeping posture may also cause the clavicle bulge to be large on one side and small on the other. In addition, it is also necessary to consider whether it is due to disease factors, such as bursitis, lipoma and trauma.1. Bursitis: It may be caused by traumatic factors, or infectious factors, or if you have joint disease, it may also cause bursitis. Usually there will be joint swelling, muscle stiffness and pain, etc. When the local skin is red and swollen on one side, it will cause the clavicle projection to be large on one side and small on the other. 2. Lipoma: Lipoma is a benign tumor, and the cause is considered to be related to genetic factors and chronic inflammation, and it occurs in the extremities and the trunk of the body, resulting in a single or multiple local lumps, and when the lumps are distributed to the clavicle on one side. If the lump is distributed to one side of the clavicle, it may appear that the clavicle bump is large on one side and small on the other; 3. Trauma: If one side of the clavicle is hit, it may cause the subcutaneous capillaries to rupture and the local skin to bruise and swell, resulting in the clavicle bump being large on one side and small on the other.