According to your history, I think you must have sinus infection( called sinusitis
). As you have allergy
, after an attack of an allergic rhinitis
, secondary bacterial infection can take place in your nose and this can cause sinusitis. This sinusitis can drip backside in your throat and causes Phlegm. So, you are advised to consult to ENT Specialist
, he will find the cause of sinusitis and he will advise the treatment of cause of sinusitis. Follow his treatment and you will be all right. Have a speedy recovery!