The sharp pain will most likely be due to a cavity in your right molar tooth. Using only your left side for chewing would have strained your left side joint and muscles around the lower jaw. That is probably why you have pain on the left side now.
Next Steps
visit your dentist to get your right molar checked and get the necessary treatment done. chew on both sides after that.
Health Tips
chewing on one side alone can cause multiple problems apart from the pain. get treatment as soon as possible and start chewing on both sides.