Bursitis is a painful condition that affects the small, fluid-filled sacs that cushion the bones, tendons, and muscles near your joints. Bursitis occurs when these fluid filled sacs, bursae, become inflamed.
Shoulders, elbows, and hips are the most common locations for bursitis. It is possible to have bursitis at the knee, heel, or base of the big toe, too. Bursitis is often associated with joints that undergo repetitive movement.