Inflammation. A bursa is a fluid filled sac rthat sits between muscle or between muscle and bone and assists with normal motion - like the ball bearings of the body. If a bursa becomes inflamed - by acute trauma, repetitive motions or activities or other forms of inflammation it causes local pain, possible swelling and usually loss of motion of the affected area.
Inflammation. Bursitis is inflammation typically after activity it usually affects either the deltoid bursa of the shoulder or the trochanteric bursa of the hip. Recommend ice, nsaids and rest to alleviate symptoms see an orthopedist if symptoms persist.