Can you please explain why swollen feeling, burning feeling after

[tlcha]

Had root canal yesterday. Before I had root canal I had wisdom teeth extraction on left side 3 months ago. Then I had 2 filllings done on 2nd molars also on the side the root canal was done. After having fillings I experienced immediate pain after one of the fillings. Also a ton of presssure that feels like my gums are swollen even though they are not to look at . I thought after the root canal the pressure and swollen feeling would go away. The feeling is both on upper and lower of the left side where all this dental work was done. The reason I had root canal was because the endodontist said I had inflammation. However she said she couldnt see it on xrays. I thought that you should be able to see that on xray. That is concerning to me. I also test to the cold test on that upper 2nd molar. I was very sensitive to cold. I still question the composite filling that was put in that tooth because it was between teeth and I wonder if it caused all this. I also question the clamps that were used for compsotie filling because after returning home from filling it caused immediate pain and pressure that stayed with me. So now after having the root canal I feel a burning sensation in gums plus that soreness and pressure or swollen feeling still on both upper and lower left side in molars and possibly gums.My endo has me taking 800 mg of ibuprofen 3 times a day. It helps just a little. Its only been 2 days since root canal. Has anyone had this happen? What could be going on? It's like my life got turned upside down going to the dentist. I did good after my wisdom teeth surgery. This all started from going to dentist to get fillings and now endodontist. Does anbody have similar experience or is there a professional out there that can shed some light on what this could be?