Bursitis is inflammation of the bursa. A bursa is a fluid-filled sac which provides a cushion and reduces friction between bones and tendons or bones and muscles around a joint. A bursa can be irritated and become inflamed due to repetitive stress, trauma, arthritis, gout or infection. Bursitis most often occurs in the hip, knee, shoulder and elbow. Symptoms of bursitis include swelling and warmth over the joint, joint pain when you touch the joint and stiffness when you move the joint.