Was told by doc that a large hard lump on my clavicle not near my neck was just a tendon sheath cyst- he barely looked at it should i get 2nd opinion?

Yes: If you are unsure, it never hurts to get a second opinion. Because there are not really any tendons that run very close to the clavicle, it would be pretty unusual (in my opinion) to have a hard lump on your clavicle to be caused by a tendon sheath cyst. Thank you for the question.

Yes: I would recommend at least a detailed physical examination and some type of imaging - usually xrays to start.