Hit on head 2 days ago by piece of metal, have awful headache/lump on head and just woken up with pain behind right ear below the bone. help?

Head trauma: Any head trauma needs to be taken seriously. Depending on how hard the trauma was, a fracture can occur and/or blood can pool quickly: local swelling under skin (hematoma); under skull; in brain causing a concussion or worse. Ice lump and call your PCP asap.

Get evaluated: I would highly recommend going and getting evaluated with imaging to rule out a brain bleed with or without skull fracture. These can be rather insidious and come on slowly and then very suddenly and sometimes even cause death if not treated in a timely manner. Time is of the essence.