You can run this utility http://etrecheck.com to get a good look at your System config. for conflicts & issues.
Also To trouble shoot further you can:
Try a SafeBoot https://support.apple.com/en-us/HT201262
Takes noticeable longer to get to the login screen, does a 5-10 minute disk repair before it fully boots up, and certain system caches, dynamic loader cache, etc. get cleared and rebuilt.
This test will tell you if third party interference; extensions etc are not loaded in safe boot mode.
Test issue in another user (or guest user) account https://support.apple.com/en-us/HT204443
This will tell you if it a universal issue or isolated to your user/admin account.