If the swelling is arising from the clavicle
,it could be bony swelling.
If the swelling is arising from the area above clavicle,FNAC(Fine Needle Aspiration Cytology) of the swelling will confirm the diagnosis.
Please meet a general surgeon
,get it examined clinically .Ask him for FNAC.
As it is painful,it could be due to infection and inflammation.
I prescribe antibiotic and anti inflammatory medicine initially to my patients with similar complaints.
Wish you good health