Trochanteric bursitis is inflammation and swelling of the bursa (fluid-filled sacs that cushion and protect tendons, ligaments, and muscles) in the area near where the femur (thighbone) projects outward, which is an attachment site for the gluteal muscles. Hip bursitis may result from injury, repetitive rubbing, or pressure within the hip. It is the most common cause of hip pain.
Source: Verywell Health