For the last few weeks I have been stretching my hip flexors and also the rest of me for walking and jogging. I have been working more on my hip flexors because I have been having some pain when I turn to go to the left. The discomfort is primarily in my left hip and it is a sudden pain and then goes away. I was suggested to keep stretching my hip flexors and to also strengthen my glutes since I sit all day in an office.
Here is a good link to show how to properly perform the hip flexor stretch. I also use the method that allows you to use a couch or a bed which really puts pressure on your hip to stretch them out.