You haven't describe the nature of your pain, but seems like you have done a restoration on right side lower premolar, it's a large restoration and since the adjacent tooth is missing there is A chance that you might have developed cracks either in restoration or tooth due to which you might be having pain.
You might need rct of your lower premolar on right side.
On left side the x ray is not clear enough to reveal the cavity/ caries.
It has to be co related clinically, but still there is a chance you have developed a cavity in lower left side second molar.
Next Steps
visit to your nearby dentist, get a check up for in particular lower left Second molar and right side premolar.
Health Tips
take pain killers for pain relief.
please describe the nature of pain to your dentist to help him/ her a proper diagnosis, hence mark what food or activity is causing you pain in particular.