Hi..
There can be a lot of reasons for the symptoms you have mentioned sometimes the pain is due to problem in the localised area and sometimes it can be a referred pain from some other area.
It could be due to problems in your TMJ joint, some unknown trauma , sinusitis, ear infections, referred pain of migraines sometimes ,any other cavities besides your 3rd molar etc
But to reach onto to any conclusion we need to do a physical examination as well as a radiological examination.
Next Steps
Visit your dentist soon for a proper diagnosis
Health Tips
You can take medications for pain and try using ice pack till then