When you're first injured, ice is a better choice than heat. It numbs pain and causes blood vessels to constrict, which helps reduce swelling. Ice is especially helpful for the first three days or so. After that, heat can increase blood flow to an injury, which may help promote healing. Heat also serves as a muscle relaxer, which can help with pain relief. Tendons are bands of fibrous tissue that connect muscles to bones and help muscles initiate and control movement in your joints. Tendinitis usually occurs when repetitive motions, stress or repeat injuries irritate a tendon over time. The result is pain and swelling in the tendons around a joint, such as your ankle, elbow or shoulder. Your tendons become less flexible with age, so tendinitis is more common as you get older.