As per your description you need to be seen by your ENT specialist again as you are suffering from last few months(since January).
Possible differential diagnosis may include Sinusitis,Pharyngitis.
Even you have eustachian tube blockage which can result in intermittent popping sound in nose and pressure in ear.
Also as you have yellowish mucus so it indicates bacterial infection.
So you may require antibiotics as well.
Your doctor may also advise you X-ray of paranasal sinuses and throat culture for further evaluation.
I understand your worry about throat cancer however as per your pictures chances of tumor are less.
Even as you have no history of smoking,alcohol so usually these are contributing factors in tumor.
Most likely these are mucous cyst of the oral mucosa which are usually benign.
If you are still worrying then you should go for biopsy of suspected lump.
Hope this helps.
Please rate me high if you are satisfied with our conversation.
In case you have further query press reply to expert button.
Bonus and positive feedback are appreciated.