I have an unexplained significant bruise. normally i wouldn't care, but it has gotten worse, and it's starting to hurt and cause pain /tightness and t?

Ecchymosis: Simple bruises, even unexplained ones, should not be painful or tender as a rule unless they're from an injury. Perhaps you may not recall a trivial trauma. It would be concerning if other unexplained ecchymoses or nose bleeds,etc appeared in other areas of your body. In that case a physician or hematologist should be consulted as platelet disorders or other blood dyscrasias would be suspected