One of the first things I do after looking at the coefficients is to look at the residuals.
You can see all of the residuals by using the residuals() function:
residuals(PainGLM, type="deviance") # residuals
For many good models, the residuals will be scattered around zero, and will have roughly the same variance at all levels. The deviance of the residuals for this model are listed within the summary section shown previously. We can see that the distribution is balanced since the absolute values of the min and max are approximately equal, as well as 1Q (25th percentile) with 3Q (75th percentile):
Deviance Residuals: Min 1Q Median 3Q Max -2.7638 -0.5904 -0.1952 0.6151 2.3153
If we want to look at the mean, we can ...