Hi,
SM13 - Updates are pending
Check whether you have your "update" active or not?
If it is active, double click on update requests and check where these updates are getting terminated (Check for ABAP dumps). There are several reasons to this, Ex: Inactive update process, unavailability of number range, database related issues, program issues etc.
SM12 - Locks last for a long time
Check whether you have long running processes (Dialog/Background)
If you do not have any long running job, then you may delete the lock entries which are not released by system
Regards,
Nick Loy