I am having the exact same issue. I started a discussion here a few hours ago. I started having pain in my thigh for a while and now I have pain in my hip. I thought maybe I was walking too much on the treadmill. I am 76 years old and have been trying to walk 4 miles a day either outdoors or on the treadmill. I was doing 2.3 MPH but had to reduce it to 1.2 due to the pain. If all of this continues I will have to ask for a consult with my orthopedic surgeon. I was terrifed of surgery 2 years ago and I am putting off the phone call to him hoping that if I slow down I will be able to manage the pain by myself. I also think that it might be a stem problem but that might not be the reason for the hip pain.