Left tonsil swollen, neck cracking pain.

I have left tonsil swollen with severe neck cracking pain as I'm suffering from last 6 months. I have 4 years of smoking history and quitted smoking 6 months before. I have done 2 USG scanning which reported normal along with blood test and TB sputum test is also normal. Doctors saying it is due muscle pain in neck. But if I eat spicy food it will give a burning sensation and not for hot foods, other things I can eat comfortably. Few days back I found mucus with streaked blood. I went to ENT doctor at that instant, he advised some medicine and called to come back after 5 days to get an nasal endoscopy. I just want to know is the symptoms relevant to nasal or due to smoking. And pls suggest what is the step to be taken to clear the doubt on cancer or other disease. Thanks