Hi..
Welcome to HEALTHCARE MAGIC..
I have gone through your query and can very well understand the concern..
As per your complain if the yellow lump is over the gums behind the molar in the region of wisdom tooth  then it can be due to inflammation of the gum flap over the wisdom tooth as a result of infection and this can also cause 
sore throat and throat pain..
The other cause of lump if it is in the throat it can be due to bacterial infection ( 
strep throat) leading to sore throat..
I would suggest you to consult an ENT  expert and get evaluated
In case of  inflammation of gum flap removal of the gum flap along with antibiotics like 
Amoxicillin 50mg thrice daily , painkillers like Advil twice daily and Pantopzazole 40 mg empty stomach once in morning can help..
In case of strep throat antibiotics like 
Azithromycin, antihistamine like 
benadryl and painkillers and warm saline gargles can provide relief..
Avoid spicy and hard foods to prevent irritation..
Hope this information helps and thanks for writing to Healthcare Magic..
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