Hi..
Thanks for the query..
As per your complain it seems that sinus congestion, along with cough,
post nasal drip and headache seems to be due to inflammation and infection in sinuses..
Bright yellow nasal discharge is due to drainage of infectious mucous from sinuses and as the sinuses drains through nostrils there is drainage through nose..
Taking Advil along will not cure infection and you need to take proper antibiotics ad other remedies should be followed..
I would suggest you to consult an Otolaryngologist and get evaluated and a thorough clinical evaluation and investigations like PNS view x ray or MRI scan can help in diagnosis and treatment can be done accordingly..
You can be advised a course of antibiotics, anti-inflammatory painkiller like
Ibuprofen, decongestants like Pseudoephadrine, do saline
nasal irrigation, steam inhalation and use a humidifier in your room..
You can also be advised decongestant nasal sprays containing
Xylometazoline or
Oxymetazoline..
Avoid spicy and chilled foods..
Do warm compresses around nostrils..
Hope this helps..
Regards.