Depends on what you mean by "main". There'll be a lead mechanic, there'll be a foreman or floor supervisor, there'll be a supervisor.
Client?!
Client?!
To find a good Mechanic or Shop call the B.A.R (Bureau Of Automotive Repair) and ask for information on the best shop in your area...
newsagent
Bob Thomas Automotive Repair. They advertise tune ups, repairs, oil changes, body services, and otherwise. They are your typical automotive mechanical shop.
Shop Assistant
Shop Assistant
A mechanic
A florist is a person who works in a flower shop.
A Counter person.
A person who repair bikes is a bicycle mechanic. A shop that handles bikes is a bicycle shop or a bicycle store.
call a local automotive body shop. Make an appointment, and get an estimate.