hi there, the cold is causing post nasal drip which is causing the tickling sensation in your throat leading to the cough.During a coughing spell the diaphragm contracts and the pressure in the chest wall is increased leading to increased blood flow to the upper part of the body including the face which is the reason for the bloodshot red look. If logenses are not useful you could try taking cough sedatives. Sometimes keeping a small piece of ginger or clove in the mouth also helps.,take care.

HI I have gone through your mail and as you said you have tendency of getting recurrent cold,post nasal drip (tickling something in throat from back part of nose),severe coughing which causes difficulty in breathing and affect your working.At present you are not getting relief even by taking lozenges. Considering your all complaints I would like to advice you to go for these basic investigations like- (1) C.T.Scan paranasal sinuses,(2) X-Ray chest P.A.view (3) culture and sensitivity of nasal discharge & throat swab,(4) Blood-C.B.C.,E.S.R.,Blood sugar,after this you should contact your E.N.T.specialist for examination of your nose and paranasal sinuses to rule out rhinosinusitis and also examine throat to rule out any local pathology in throat as ulcer or growth,ann examine chest to rule out any asthmatic condition of respiratory system.In this way by co-relation of physical observation with inferences of investigations your correct diagnosis may be made and that can be treated accordingly.Thanks.