If you have lactic acid build-up in your shoulders and neck, you can eliminate it by the following ways: 1. Self-stretching and massage of the shoulder and neck muscles, first find a chair with a backrest and sit down, lean on the chair, lift the collar with both hands, tilt your head back and look at the ceiling, the time for self-stretching is about 5 minutes, use the weight of your head to stretch the neck muscles backwards to promote muscle relaxation, after 5 minutes, massage the neck and shoulder muscles with both hands to promote the elimination of lactic acid. 2. 2.Heat compress, use hot water bag or hot towel for neck and shoulder, 15 minutes each time, 4-6 times a day. 3.Oral anti-inflammatory analgesics and muscle relaxants, commonly used anti-inflammatory analgesics are non-steroidal analgesics, such as Celecoxib, commonly used muscle relaxants are Eperisone.