I have a hard mass, the size of a quarter , an inch down from the collar bone, center of high chest area. it feels tender, like a bruise . ?

Interpectoral node: Unless you are feeling a cystic lesion under the skin, the most common lesion presenting as a hard mass is a Rotters node. This is a malignant interpectoral lymph node between the pectoralis major and minor and represents metastasis to this particular node. It should be checked by a surgeon, and then correlated with mammographic findings and possibly then biopsy needed.

Uncertain.: Could potentially be a breast mass, abnormal interpectoral lymph node, or possibly hypertrophic arthritic change of the sternoclavicular joint. First step is to see your doctor for an evaluation and next steps.