'Bursitis is a painful condition that affects the small fluid-filled pads — called bursae — that act as cushions among bones and the tendons and muscles near joints. Bursitis occurs when bursae become inflamed.
Tendinitis is inflammation or irritation of a tendon — any one of the thick fibrous cords that attaches muscle to bone. The condition causes pain and tenderness just outside a joint.' (From the Mayo Clinic)