Been having extremely bad pain in left side of face especially my cheek all the way to ear and teeth. hurts to chew. also been having yellowish brown?

Yellowish brown what: Many possible causes for pain including, but not limited to: tooth , gum, sinus infection, jaw joint dyscrasia, etc. Please see your Dentist for differential diagnosis and treatment plan. This probably isn't a DIY project, get professional help.

Oral surgeon: your problem sounds complex enough to seek evaluation by an oral surgeon.

Tooth Abscess: The only way to cure a dental abscess or gum infection is with dental treatment. See your dentist.