(HealthDay News) -- Bursitis occurs when the bursa, or fluid-filled sac between bones in the joints, becomes irritated or inflamed.

The bursa in the hip joint is rather large and can easily become irritated, causing hip pain. The pain may be sharp or a dull ache, and may worsen after lying on the hip or sitting for long periods.

Here are some common causes of hip bursitis, courtesy of the National Library of Medicine:

• Repeated stress on the area, from running, biking, climbing stairs or standing for a long time.
• A hip injury, including falling on it, bumping or bruising it, or lying on it for a long period.
• Scoliosis and other diseases of the spine.
• Legs of unequal length.
• Rheumatoid arthritis.
• Hip surgery.
• Bone spurs or calcium deposits in the hip.