CNN accuracy and loss doesn't change over epochs for sentiment analysis
You have imbalanced Data, that's why your network always predicts the most frequent answer (he is in a local minima).

There are solutions to avoid this kind of problem:


Balance your data, use as much "good" as "bad" in your training set.
Change your cost function,  e.g. the cost of error on "good" should be higher than "bad".


(don't use both at the same times or your model will be imbalanced in the other class)

If you look for imbalanced data on google you will find lot of articles on this problem, since it is common.