The most common reasons for one side of the clavicle to become bigger are unbalanced force, bone spur, fracture, tumor and so on. 1. Unbalanced force: If the patient has a long-term bad posture or unbalanced muscle force, it will easily cause one side of the clavicle to protrude, which will be manifested as enlargement. 2. Bone spurs: If the patient’s clavicle has bone spurs, bone proliferation has been formed at the edge of the normal clavicle, which will show that the clavicle is enlarged. 3. Fracture: If the patient has a fracture on one side of the clavicle, the fracture may not heal well during the healing process, and the fracture site is also prone to enlargement. 4. Tumor: If the patient’s clavicle has a bone tumor, it may also show up as enlargement of one side of the clavicle, which usually needs to be examined in time. There are many reasons for the enlargement of one side of the clavicle, if the symptoms continue to be unrelieved, it is recommended to go to the hospital in time to find out the cause of the disease, and the doctor will carry out targeted treatment.