Pain after one WEEK of going to the dentist?!

Pain after one WEEK of going to the dentist?

I had one of my teeth filled, and it is senditive now (after 4-5 days), even when I drink water. Went to my dentist, she said it's normal and it's because the filling was near the gum. That's the first time that I hear that. I thought you go to dentist to get rid of the pain, and not develop some new pain (I hadn't any pain in first place and went just for a checkup).
I hate to think that she hasn't done it right or if she's lying or hiding something.
So please somebody tell me that he/she had the similar experince?

Please only serious replies.
Thank you and have a very good day.

Your dentist is right on the money. Cavities next to the gumline are also closer to the nerve in that area because of the shape of the tooth structure it narrows down by the gumline. Filling and recession at the gumline area can be quite sensitive and if your dentist would have left that cavity you would be looking at a root canal or extraction of that tooth. You can use Sensodyne toothpaste, that is the best on the market and after you brush your teeth take a little dab of the Sensodyne and place it right on that area, don't rinse it off. This also works best right before bedtime. If the sensitivity does not gradually diminish after 2 weeks yo may need to consider a root canal or extraction, but I would consult with your dentist again in about one more week.