Tendonitis is pain in or around a tendon, which is a band of strong tissue that connects a muscle to a bone. Tendons bend, stretch, and twist to help joints and muscles move. They can become inflamed ...

While tendonitis is often caused by stress on a tendon from repeated motions, that’s not always the case. Calcific tendonitis is caused by buildup of calcium on a tendon. You can develop calcific ...

Medically reviewed by Amy Kwan, PT Key Takeaways Patellar tendonitis happens when the tendon becomes inflamed and irritated.