I have a bony lump at the second costochondral junction on the right side. If I lift my arm , it is visible, probably 2x1 cm. It is completely painless. I noticed it almost two years ago. It does not seem to change in shape or size but in the last week i have been poking it so much, it seems bigger now. I am extremely worried that it could be a tumour rather than a callus formation. I have no history of any other major diseases, no familly cancer history, but I am a light smoker. I do not remember having trauma except laparoscopy for gall blader removal more than two years ago. Any sugestions would be greatly appreciated. Thank you!