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.

While tendinitis can occur in any of your body’s tendons, it’s most common around your shoulders, elbows, wrists, knees and heels.

Some common names for various tendinitis problems are:

Tennis elbow
Golfer’s elbow
Pitcher’s shoulder
Swimmer’s shoulder
Jumper’s knee

Source: Mayo Clinic Staff