restarting database while shrink [db] is still running
Restarting SQL Server is rarelly a good way to fix issue.

You can try to log as a dedicated admin (DAC connection) and then, you will see what is running and you may be able to kill some session.

Be aware that by killing a session, SQL will have to roll it back (which is single threaded) and there is no way to escape from this rollback. Sometime, the best solution may be to wait for it to complete. (You can kill the select as the rollback should be pretty quick)