Thanks for the query to H.C.M. Forum.
Since , how many days ,you are having lump on left side of neck.
May be , Parotid gland
enlargement ,Submandibular gland
enlargement, Tubercular lymphadenitis
Inflammation of effected part.
Physical examination by a surgeon / physician will help you.
E S R is important in this case, if it is very high ( > 100 mm of Hg) than it may be due to some chronic infection like tuberculosis
Hope I have answered your question.
If further any question I will help.
Get well soon.