Hi dear welcome to HCM.... In post nasal drip excess mucous can be there.... If tonsilitis is there tonsil can be enlarged in size ..... But you are saying growth seen over pharynx wall. ... So it could not be from post nasal drip.... The detail history needed like pain during swallowing ??? Smoking ??? Duration ??etc. Along with I think you should get examined your posterior pharyngeal wall by physician and if needed biopsy taken for rule out its nature . For enlarge tonsil swab can be taken and and for culture and sensitivity. ... According to cause treatment given .... Like by steroid, antibiotic or surgical excision of growth ... Take care ... Hope I have solved your concern ....