Can you work on Sundays in any of the following jobs?: 
1. Security guard for a building guarding an empty building.
2. Truck driver that delivers food or medical supplies.
3. Locksmith.
4. Roadside assistance.

This last weekend I wasn't thinking when my boss asked if I could work from 7 PM on Saturday to 7 AM on Sunday and I said yes, so I worked 
Sunday as a security guard just guarding a building making sure there weren't issues. 
So I was wondering if that was sinful, and the other professions I listed I was just curious about because I might do them in the future. 

The jobs you mention seem to be 'of necessity' to the health, safety, and well-being of others.  If so, you may do them on Sunday if it is necessary for you, personally to meet your obligations or your presence is necessary to others.  If at all possible, you should hear Mass as well.  If working precludes ability to hear Mass, then try to limit the number of Sundays you work in order to sometimes get to Mass.  Also, if you must miss Mass, try to get to a weekday Mass.  
If you are a Home Aloner, you may work, but do set aside enough time to have a Holy Hour.  The goal is that you have kept the Lord's Day Holy.

Working on sunday is very grace according to St John Vianney 

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...very grace...?

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...very grace...?

"c" is next to "v" on the keyboard.  "Very grave" makes sense in the context.

I still have enough time to get to Mass.
But I just found out I will be required to work Sundays now so I guess the question is no longer relevant.

Speak to your confessor about your particular situation and see what he says. 

In this rare instance, I must agree with the resident CI liberal, poche.  Ask a priest for advice before deciding what to do. Such matters are best dealt with on a case by case basis.  The world is no longer a place where most people honor God By setting aside an entire day for Him.  If it were, then there’d be no reason to question.  In my estimation, the jobs the OP mentions do fall within those who are allowed, even whose duty it is to be on the job on Sunday.  Medical supplies and food must be delivered, people need assistance, and security must be maintained.  
Has anyone out there ever visited the ER or Urgent Care on Sunday?  Ever had a car break down on the way to or from Mass?  Ever needed to stand guard over property or summoned the police?  Imagine if you got sick, went to the ER and found it closed because it was Sunday?  Or you had to stay overnight stranded on the highway until Monday morning?  Or while you were away at Mass, thieves break in and you come home to find your entire inventory and source of livelihood gone?  
This doesn’t mean I support a Home Depot’s policy, just that some Sunday work is permissible, even a form of sacrifice for the Catholic who misses Mass in order to serve others in need.  
(Most people do not NEED to shop at Home Depot on Sunday.)