hi does anyone know if these symptoms are a sign of lung cancer........six months ago i got a dull ache in the bottom of my back , in the last four weeks this has turned to a pain and this has started going up my spine and around my left ribs as an ache, i also have leg numbness in both legs , i have an ache in the back of my head, sometimes a headache , and i seem to have a salty taste coming up