You probably have a sinusitis and a faringitis. As the characteristics of the mucus seems to be from a bacterial origin you should probably see a doctor to advise you the apropriate antibiotic. Amoxicilin 500 mg every 8h (three times a day) seems like a good option. Paracetamol 1g will help with the pain (do it only in SOS until a max of 3 a day)
Sinus infecion yellow is pus.