Looks like generalized weakness with anemia

First of all you need to quit cigarettes as it's not good for your health. Whether it's simple upper airway disease or lung disease it can aggravate both. Cough with an itchy throat can also be increased with cigarette smoking Also need to have more details about type of cough whether dry or with mucous, it's colour. Etc Take anti-tussive syrups if it's with mucous else take antihistamine medications for relieve of symptoms for 7days if not relieved consult ENT doctor

Quit smoking it doesn't look any serious thing. Tablet Allegra M at night steam inhalation

Regular cough can cause Post nasal drip of mucus which might lead to an itchy throat. Again for breathlessness there's still many causes but for that u need to consult ENT in person to look for your nose for septal deviation and also get your nasal endoscopy done that might help u to less worry from thinking about the cancer.

Do you have expectoration in cough or is it dry? Also you should consult pulmonologist once

Cancer screening in this case includes an FOL guided screening of the upper aerodigestive tract and screening for any cancerous or precancerous  lesion. Smoking index evaluation is important.

Warm water gargles