Thank you for your inquiry. To answer your question in general, yes your root canal can be done through your current crown/bridge. This is common practice but please keep in mind that if/when this is done, there is a risk that your crown/bridge may fracture in doing so. If you're having jaw discomfort, you may have another issue occurring aside from your root canal, as root canals are typically associated with discomfort with temperature. If your crown/bridge was recently placed, then make sure your occlusion (bite) is ideal. You can also look into wearing a night guard that may help with possible grinding you may be doing to cause your jaw discomfort. Either way, give it a bit of time to all subside but continue to monitor and treat as needed. We hope this helps and wish you all the best!