Hello and hope you are doing well.
The one sided facial pain could be due to maxillary sinusitis, if it is accompanied by nasal stuffiness and sometimes a post nasal drip. It could also be due to tooth infections, impacted tooth or skin infections. The others are migrainous headaches and those caused due to brain disorders, disorders of the eyes , neck or ears to name a few.To find a cure you need to consult your primary care physician for proper assessment.In the meantime take OTC naproxen for relief from pain. Regards.
Hope this helped and do keep us posted.