Dear Jeanne:
Sorry to hear about your hip problem. Pain in the outer hip can also be from an entrapment syndrome. It is often seen in overweight people, diabetics, pregnant women, or people who wear either tight clothes or belts. The pain would follow a dermatome of L2-L3. Bursitis can also cause pain, but would be more generalized in the hip, but I guess could be outer hip but would not follow the above dermatome. The chronic pain might cause a very mild gait change and thereby involving the knee or calf in your case. I do not know what might be the cause of your early fatigue with exercise. Sorry, without being able to see and examine you, my trying to give you help is severely restricted.
CCF Neuro MD
Please forgive my medical terminology but the Mri/with contrast of the head focused on the ears but pictures were obtained of the head as well. I was seen by neuro-otology.