It Seems Like I Have A Severe Nuerological Pain That's

It seems like I have a severe nuerological pain that's about 3-4" in diametor, mostly worse at tnight and prevents sleep in my upper buttock area. It's not surface and in that specific area. This has been ongoing for two weeks. I'm 75 years of age and extremely good health I'm 5'8" and 125 lbs. I'm very active and eat healththy and have not had other medical problems. What might be looking at?