Pain in the side of face could be due to injury to a nerve or pinched nerve, an infection or a trauma. Hence it could be Trigeminal neuralgia, abscess in tooth, exposed root canal, internal ear infection, maxillary sinusitis, TMJ, migraine, herpes (recurrent) without rash or fibromyalgia localized to face. Please consult your doctor regarding this immediately. Take care!
The medical advice given should not be considered a substitute for medical care provided by a doctor who can examine you. The advice may not be completely correct for you as the doctor cannot examine you and does not know your complete medical history. Hence this reply to your post should only be considered as a guiding line and you must consult your doctor at the earliest for your medical problem.