McBTC I am not a doctor, but I would be surprised if this were arthritis. The location (to my uninformed mind) is not in the right place. The pain is next to iliotibial band (slightly to the rear of it) way on the outside of the hip.
My biggest fear is that it will be some back related issue that is a tough diagnosis and/or treatment with risks and/or unpredictable outcomes. Arthritis really doesn't scare me as I seem to be afflicted with that in multiple places and would be surprised if the hip were an exception here - just a matter of degree.
If you were to kind of list the 'working joints' in order of pain that they give me on a daily basis (knees, ankles, hips, shoulder, and back), hips and back are last on the list (until 12 or so days ago).
dave