Massaging diaphram and stomach for gerd? Sternum area

Noticed I have a LOT of pain when I press down slightly below my sternum. Almost a horrible muscle spasm pain. Which considering for 15 years I've been saying I feel like my chest is ripping apart, maybe I do have a muscle spasm there I certainly feel like I do. If I massage into this area it hurts tremendously. Did have hiatal hernia surgery 3 years ago. Thoughts?