!sym noisy
will tell you why it did not want to load the pdb. Perhaps you did rebuild your driver and the pdb guid or pdb age does no longer match. If you are sure that you have built the same source files you can force loading of your pdb by
.reload /i /f yourdriver.sys
/i is the magic switch to load also mismatched pdbs. This switch will not load any driver from your symbol server but it will consider only local file paths to load your driver. Also symbol store directories (SRV*) are not considered since there would be many versions to choose from. But if your .sympath directly points to your pdb it will be loaded.