Noticing pain in cavity

It's me again. The worry wart.

So I already went to my new dentist and got a cavity diagnosed. (What a saint. I sent my coworker to him too!) I have an appointment to fill it in two weeks. Now I'm noticing pain. It's only every now and then, and only for like, 30 seconds, at most. He didn't say I would need a root canal, but is it too late to get a simple filling, because I'm experiencing some pain? I've only had cavities without pain so I'm not well experienced in this