The arm is stretched because of some bad posture or excessive posture, resulting in muscle or tendon strain, the specific treatment methods are as follows: 1, more rest: avoid doing similar actions again, as well as some of the actions that will induce pain, but also pay attention to the brake, avoid cold, local hot compresses. 2, medication: if the pain is serious, you can take oral celecoxib, external FUITALIN ointment. Stretching the arm, within two weeks to pay attention to avoid strenuous exercise, avoid all will induce local pain movement. If there is no significant improvement in two weeks of observation, it is recommended to do a magnetic resonance, to exclude the possibility of some tendon or muscle ligament rupture.