Hi. Welcome to HEALTHCARE MAGIC.. I have gone through your query and can understand your concerns.. As per your complain feeling of something dropping at the back of throat seems to be post nasal drip and as you also have pain in sinus area there can be Sinusitis and post nasal drip seems to be secondary to sinusitis.. The thick saliva that you experience can be thick infected mucous that is present in the sinuses being drained off.. White patches over the back of tongue can be due to excessive yeast growth leading to thrush.. You should consult an ENT expert and get evaluated and a thorough clinical evaluation and investigations like PNS view x ray or MRI of the sinuses can help in confirming the diagnosis and treated accordingly.. He/she can advise you to take antibiotics like Doxycycline or Clindamycin, anti-inflammatory painkiller like Advil or Aleve, decongestants like Phenylephrine, mucolytics like Ambroxol or Bromohexine, warm saline gargles, steam inhalations and using saline and steroid nasal sprays.. Do warm compresses over the sinus area that is around the nose.. Hope this information helps.. Thanks and regards. Dr.Honey Nandwani Arora