I had hip pain quite often. Left side... later I found out that my left leg is marginally longer than the right.
After starting deads and squats the pain is gone.
Go see a !good! doc.
My doc told me to play tennis to remedy the situation
I'm guessing your doc said that cause the forward facing side to side motion you do in tennis with help strengthen the muscles in this area. Your gluteus medius can have much to do with this as it gets little work in regular training. I have had this hip pain but it comes on as a strain while exercising heavy, squats or leg presses. Standard rehabilitation practices should have you doing well in a few weeks. Ice and ant-inflamatorys also help and should be included.