Is lung cancer curable?

I want to know if lung cancer stage 4 (or higher,I don't know) is curable at all or not.

Is Chemotherapy the only solution?
are there any kind of medicines or diets which reduce the size of tumours and destroy them in the end?

Is radiotherapy used for stage 4 and severe cases? or is it done along with chemotherapy?

one more question.... Excuse me! I'm kinda confused ! I've heard if there exist tumours in both lungs the possibility of having a blood cancer is very high! is that true?

The patient with lung cancer has no pain in any part of his body? Is it a good sign or not?

Thanks a lot everyone....please reply if you have any accurate information regarding to any of above questions.