i read your problem.pain can be of various reasons
and is not always accompanied by swelling or abcess.
there are chances you might have deep caries ,your
gums are infected because of food lodgement or
may be wisdom tooth erupting.
get it diagnosed clinically by a dentist
and get a xray
done of that area.
kindly never take expired drugs as these may cause harm
you can take amoxicilin 500mg twice for 5days with
painkiller like diclogesic
under doctor prescription.
rinse mouth with warm saline water .