Tooth and Jaw pain

I am in very good dental health, regular cleanings and x-rays. No pain or dental problems, ever. I’m a major city in the west coast.

Three weeks ago, I had several “deep” cavities filled. From my point of view, the experience seemed more exhausting than usual, and I kept my mouth open very wide for long periods. Some bands were used on some teeth, for some reason.

That night, I developed a very painful sensitivity in those teeth, but it slowly spread to that entire side of my mouth and also the bottom of my jaw on that side.. 

I went back a week later, two weeks ago, and the dentist looked and made some minor adjustments to my bite. He also took x-rays of the entire area and told me that there was nothing alarming going on that he could see. At that point, I was more or less dismissed and told that if it didn't get better, I should see a specialist and maybe needed a root canal.

Now other teeth, even teeth on the other side or my mouth, are aching, so I have some aching teeth more or less everywhere. This is not a sharp pain, it's more a very painful ache. It is sensitive to hot and cold. It feels something like I would feel if I had a sinus infection, a dull pain, but don't have something like that and it is also on a few teeth on the lower jaw teeth,

Of course, at the beginning I only ate on the side that didn't hurt, and now that side is hurting, as if I strained it.

As a lay person it seems to me that the spreading of this ache to teeth which were not worked on means the root canal idea is a weak answer. Or is this wrong? l

It's clearly related to the dental work, there have been no other significant events in this time frame. 

What could be the cause of this overall ache, and cold/hot sensitivity to various teeth in different areas of my mouth (although it started on the teeth that were worked on) and what should I do about it? Could a jaw injury cause these symptoms?