Well-tuned queries - in an OLTP system - genarally should not parallellize. This is almost certainly a case of a suboptimally tuned system.
Is auto-updatestats, auto-createstats turned on for your databases?
Do you regularly carry out index defragmentation?
Are your queries properly indexed (as was already mentioned)?
Is your tempdb properly configured?
These are some of the questions to consider.
__________________________________________________________________________________
SQL Server 2016 Columnstore Index Enhancements - System Views for Disk-Based Tables[/url]
Persisting SQL Server Index-Usage Statistics with MERGE[/url]
Turbocharge Your Database Maintenance With Service Broker: Part 2[/url]