Bursitis (bur-SY-tis) is a painful condition that affects the small fluid-filled pads — called bursae (bur-SEE) — that act as cushions among your bones and the tendons and muscles near your joints. Bursitis occurs when bursae become inflamed. The most common locations for bursitis are in the shoulder, elbow and hip. But you can also have bursitis by your knee, heel and the base of your big toe. Bursitis often occurs near joints that perform frequent repetitive motion. Treatment typically involves resting the affected joint and protecting it from further trauma. In most cases, bursitis pain goes away within a few weeks with proper treatment, but recurrent flare-ups of bursitis are common.