Scoliosis will not cause a mass on your clavicle (collarbone). You do not say where the mass is located. If it is over one of the ends, it may be something going on within the joint. Malignant tumors are usually painful, but not always.
The only way to tell exactly what it is, is to see your physician, who can do an examination and order tests (x-rays, CT scan, MRI, bone scan, blood work, etc as needed).