Just a short while ago I stoped for a minute, leaving car running. When taking off again the power steering was not working. Pulled over and turned off and restarted again. Now working fine. Should I be concerned and what should I do besides check fluid level?

 

Some have electric power steering and some have hydraulic. Need to know which you have.
Need year, model and mileage. If turning off the key had an effect I would suspect it has electric power steering.
If it happens again , you may need a new steering motor

 

It is a 2011 XLT w 150,000 miles.

 

That is the year they came out with electric power steering.
It appears you will need to have that assy replaced. They are expensive and very good move to confirm before starting the job.