If you are in pain, I do not recommend you to run until you are pain free for a good week. This could be just a minor adaptation issue which may heal on its own if you give it time for the inflammation to go down. If after a week or so you are still in discomfort than you may want to contact a sports medicine doc.
The problem with a running injury is that many times the source of the pain is not the cause of the pain...in other words, your feet could be causing your issues in your hip.
For example, I was having a horrible pain just below my right shoulder blade. I spent time rolling my shoulder out and still no resolution. I went to my physical therapist and what we discovered is my left glute had a lot of adhesions and once she released them I have been pain free ever since.
While I know you have your heart set on running tomorrow, but know that taking off a few days now will hopefully get you back on track sooner than later. However, if you elect to run when you are already in pain, you may create bigger issues down the road as you could unconsciously change your gait to compensate for the discomfort, therefore creating another dilemma.
I wish you well!